4. Firmware and PLC program environment creation of architecture x86

The architecture x86 recently was positioned as embedded and it's real solutions into this industry rarely have resources (< i386), which is not enough for full-featured OS and advanced environment execution. For this reason and by reason of big the architecture unification the individual assemblies of kernel Linux and main programs of the OS environment performed rarely enough, and that typical mostly for the architecture ARM. More interest and practical for x86, for wide the hardware circle, it is assembling firmwares with compressing a root file-system (RFS). But still possible individual assembling by aid of the build systems as "BuildRoot" or "PTXDist", bottom. And also here possible direct installing a Linux distribution.

4.1. Instruments for assembling the firmware environments with the compressed RFS, based on distributive ALTLinux

The following requirements were pulled out to the implementation of the PLC firmware of the section:

• Compactness. In connection with the direct dependence of prices on industrial flash drives with their volume, as well as the reality of the needless for frequent updates, the image of the firmware need to be packed, reaching the level of compactness up to the 8-50MB at a runtime PLC in the full-featured OS.
• Uniform source repository. Since the firmware is not something unchangeable, not expandable and finally fixed, then it must be based on the real, developing-supporting repository of OS package. This will allow for a long time to form updates and expansions, not maintaining the mediated repository special.
• Debugged and simple building procedure. Given the fact that configuration of the firmware can be for some time be stabilized and in addition in the operating system's components and in OpenSCADA too it will be detected and eliminated the bugs, the procedure of building of the firmware should not be burdensome, but on the contrary — easily adaptable.
• Clear implementation of the writing mode in the OS tree. Although the firmware means the creation of packaged not modified image of firmware, but the characteristics of the PLC runtime involves the modifying of the databases and archives. In addition, the possibility of correction of the initial configuration is an important requirement.
• Reliability and stability to the sudden shutdowns. The specificity of exploitation of PLC is usually the inability to properly shutdown, as well as the practical reality of the situation instantly and unpredictable power outage. PLC in these situations must keep working, i.e. to contain the journaling file system and ensure that its verification and automatic correction of errors.
• Conditional division of the PLC configuration to two types:
  • PLC without the local display, possibly with a simple text display.
  • Touch-panels with the PLC function.

Given the above requirements, for the creation of the firmware it was chosen the tool for creating the distributions mkimage of ALTLinux. mkimage is the tool for building Sisyphus-based system on basis of template. As an initial set of templates it was taken the set of templates of formation of ALTLinux distributions at git://git.altlinux.org/people/boyarsh/packages/mkimage-profiles-desktop by the command:
git clone git://git.altlinux.org/people/boyarsh/packages/mkimage-profiles-desktop
As the basis it was taken the "rescue" template, as the most compact and close to the target PLC.

Firstly building performed basing on the package base of the distributive ALTLinux 5.1, there is present the realtime kernel from XENOMAI. For obtaining some specific packages you need to connect the repository of packages "ALTLinux 5.1" from the OpenSCADA project:

4.1.1. Assembling

Firstly it was created the configuration of PLC without local display in mind of the availability of this type of equipment and lack of equipment for the Touch-panels.

New PLC template was named "plc", it was tested on the boards of PC/104 form factor MOPSlcdLX of Kontron company, ATH400-128 of Diamond Systems company and modular PLC LP-8781 of the ICP DAS company. The archive of the resulting mkimage tree with the "plc" template can be downloaded here ftp://ftp.oscada.org/OpenSCADA/PLC (templates and materials of individual controllers are placed in their own directories).

The key points of the configuration of new template was the writing of the new init-script (rc.sysinit), the script of the after installation configuration of the firmware's image and the list of packages in the image of firmware.The first script is designed as the package "startup-plc". The second script was embedded in the template "plc" on the way: profiles/pls/image-scripts.d/01system. The list of packages was embedded in the template "plc" on the path: profiles/pkg/lists/plс.in.

The procedure of creating the firmware from the image is the following:
# Creation the configuration script configure $ ./autoconf # Configuring of the builder to generate the disks' images $ ./configure --with-imagetype=flash # Building of the image $ make plc.cd

The result is an output directory in the "profiles/out/" have look:
syslinux/ # boot-loader folder alt0/ # booting files full.cz # image of the primary initialization system vmlinuz # OS Linux kernel syslinux.cfg # configuration file of the loader plс # image of the working OS, OpenSCADA and other tools

4.1.2. Installation

It is possible to download the firmware to: USB-flash, IDE-flash and HDD. However, in the case of the USB-flash there is the problem with waiting for initialization of USB-subsystem and you'll have "to run" some dialogues.

The file system can be FAT or EXT2/3. In the case of EXT3 the root is mounted as in EXT2, because of problems in the initializer. In the case of EXT2/3 you'll need to use not the syslinux boot, but extlinux, the configuration of which is almost the same one.

Next, lets mount the medium and place the files from the output directory on it as follows.
In the case with FAT and syslinux:
syslinux/ # boot-loader "syslinux" folder alt0/ # boot files full.cz # image of the primary initialization system vmlinuz # OS Linux kernel syslinux.cfg # configuration file of the loader plс # compressed image of the root file-system with the OS, OpenSCADA and other tools work # EXT3 file system with the operational data
In the case with EXT2/3 and extlinux:
extlinux/ # directory of the "extlinux" loader (to rename "syslinux") alt0/ # boot files full.cz # image of the primary initialization system vmlinuz # OS Linux kernel extlinux.conf # configuration file of the loader (to rename syslinux.cfg) plс # compressed image of the root file-system with the OS, OpenSCADA and other tools work # EXT3 file system with the operational data

To ensure the reliable operation of the operating data stored in the file "work" with the file system EXT3. The file-system of this file is checked for integrity at the initialization. This file is created as follows:
# Creating the operating data file at 200Mb dd if=/dev/zero of=./work bs=1024 count=204800 # Creating the EXT3 file-system in the file mkfs.ext3 -m 0 work

In the case of the file system EXT2/3 on the target disk the "work" file can not be created. In this case, the working data will be placed in the directory "root" of the target disk.

This is an unreliable solution because the root file system of the target disk is not static and its check is not possible, because of earlier mounting in the "ro" and the potential unreliability of the check of the file system, mounted at "ro", as well as because of the inability to remount as EXT3.

The next step is the configuration and initialization of the loader. To configure the loader it is necessary to edit the file "syslinux/syslinux.cfg" or "extlinux/extlinux.conf" as follows:
default plс prompt 1 timeout 200 implicit 1 label plс kernel alt0/vmlinuz # To use in the case of identification of the bootable partition by the label append initrd=alt0/full.cz live lowmem fastboot stagename=plс showopts automatic=method:disk,label:PLC # To use in case of identification of the bootable partition by the identifier # append initrd=alt0/full.cz live lowmem fastboot stagename=plc showopts automatic=method:disk,uuid:4824-271E

In the case of selection the identification of the bootable partition by the identifier you can get the ID of our partition with the command: blkid.

In the case of the label it is a bit harder and this is done for different file systems in different ways.

For the file-systems EXT2/3 it is done by the utility e2label. For example: e2label /dev/sdb1 PLC

For the FAT file system it does by the set of utilities that come with mtools or with parted, easier. With mtools you can do it as follows:
# Edit /etc/mtools.conf by the line addition: drive c: file="/dev/sdb1" # Where /dev/sdb1 is bootable partition of the target disk # Setting the partition's label mlabel c:PLC

Now we can initialize the loader:
# For "syslinux" syslinux /dev/sdb1 #previously the partition must be unmounted # For "extlinux" (path points to mount point of the partition of the target disk /media/PLC) extlinux --install /media/PLC/extlinux

That is all with the boot and initialization of firmware. If the resulting disk is not loaded:

• The bootable flag is missing at the bootable partition.
• The incorrect or damaged "MBR". To check and restore it is possible by usage of "ms-sys" utility.
• Sections of the media are created or recreated with the help of parted. This utility align in strange way the partitions that do not allow them to boot on USB-flash. It is necessary to repartition the media with fdisk.
• Boot can also be not working on the old systems that do not know how to boot from USB-HDD. For them it will be necessary to adapt the geometry of the disk being arranged to USB-ZIP or something like that.

4.1.3. Result

The result is the firmware with the size from 30Mb to 100Mb, satisfying all announced requirements and it provides:

• Loading for 27 seconds from the controller's switch on and including the initialization of BIOS.
• Checking and restoration of the working file system in the "work" file.
• Storing the user data and changes of the firmware in the "work" file.
• Automatic network configuration with DHCP (or 192.168.0.1).
• Access to the controller via SSH and user-friendly interface of working, including mc. The passwords by default (root:123456; admin:123456).
• Time synchronization via NTP.
• OpenSCADA execution with the available network interfaces:
  • configuration and runtime environment via Web (ports: 10002 and 10004);
  • control interface of OpenSCADA (10005).

4.1.4. OpenSCADA

As the PLC runtime system the OpenSCADA is used. For this case we'll take the building with separate packages for each module and indicate to install the virtual package openscada-plc, which contains all the dependencies on all the OpenSCADA packages, typical used for this configuration. The package of gd2 graphics library has been rebuilt without the support of xpm graphic file format and library was called libgd2-noxpm. All this was done in order to avoid the heavy dependencies on the libraries of GUI XOrg.

The result is the runtime of the PLC with support:

• DB:
  • SQLite.
• Transport:
  • serial interfaces;
  • TCP, UDP and UNIX sockets;
  • security socket layer (SSL).
• Transport protocols:
  • HTTP;
  • self control protocol of OpenSCADA;
  • user protocol.
• Data source:
  • calculator on the Java-like language of high-level;
  • calculator on the functional blocks;
  • controllers of the logical level;
  • various PLC by the protocol ModBus (RTU,ASCII,TCP);
  • OS data;
  • hardware of "ICP DAS", for controllers LP8x81.
• Archiving:
  • on the file-system.
• User Interface:
  • Visual Control Area (VCA) engine;
  • visualizer VCA based on the Web-technologies;
  • configurator of OpenSCADA based on the Web-technologies.

The configuration of OpenSCADA runs in demon mode in locale "en_US.UTF-8" (also available "ru_RU.UTF-8" and "uk_UA.UTF-8") using the local database SQLite, providing the following default network services:

• configuration and execution environment through the Web (ports: 10002 and 10004);
• control interface of OpenSCADA (port: 10005).

4.1.5. The implementation details

In this section let examine the details of the OS tree of the firmware, the initialization script rc.sysinit.plc and the script of preparation of the OS tree of the firmware.

To build the PLC firmware it was used the following list of packages:
interactivesystem ### Startup kernel-image-@KERNEL@ rootfiles startup startup-plc SysVinit hwclock ### Common coreutils glibc-locales glibc-nss glibc-utils glibc-timezones sysfsutils sysklogd util-linux schedutils ### Disk utils hdparm ### Applications binutils pciutils procps shadow-suite ### Applications/Archiving gzip ### Applications/File less ### Filesystem utils e2fsprogs ### Applications/Networking etcnet iputils mailx openssh-server dhcpcd ntpd ### Applications/Shells bash mc udev dbus hal libgd2-noxpm fonts-ttf-liberation lm_sensors nut nut-driver nut-server watchdog ### OpenSCADA Console #openscada-plc ## OpenSCADA GUI openscada-visStation autologin icewm wm-select xorg-x11-server #xorg-drv-geode xorg-x11-utils fonts-ttf-dejavu fonts-bitmap-terminus

List of the modules of the loader's system kernel with the purpose to reducing the initialization image size was decreased to the following ones:
loop.ko mtouch.ko pcmcia_core.ko rsrc_nonstatic.ko yenta_socket.ko scsi_mod.ko libusual.ko ide-disk.ko ide-core.ko sd_mod.ko usbcore.ko ehci-hcd.ko ohci-hcd.ko uhci-hcd.ko appletouch.ko usbhid.ko usbtest.ko usb-storage.ko mbcache.ko jbd.ko ext2.ko ext3.ko fat.ko nls_base.ko nls_cp866.ko nls_koi8-r.ko nls_utf8.ko zlib_inflate.ko squashfs.ko unionfs.ko vfat.ko pata_cs5536.ko amd74xx.ko

To the script of the tree preparation there were added the following functions:

• changing the name of the distribution kit;
• replacing the init-script to "inittab.plc";
• creating the user-admin "admin" and the passwords setting by default to "123456" for users "root" and "admin";
• initialization of the /etc/fstab;
• setting locale to "en_US.UTF-8";
• network configuration;
• clock setting on the whole and the time-zone setting to "/usr/share/zoneinfo/Europe/Kiev", for changing what you need replace the file "/etc/localtime" to need zone;
• enabling of the necessary services;
• removing of the documentations, help pages and information, icons, RPM-database and apt cache;
• removing of the not needed locales and the translations; left for presence only the locales: en_US, uk_UA and ru_RU;
• selection of only used kernel modules and deletion all the others is added; it is disabled by default and can be enabled to preparation the final firmware for specific equipment;
• the directory with the kernel (/ boot) is deleted in connection with its moving to the root of the boot partition.

The initialization script (rc.sysinit.plc) was provided with the following functions:

• remounting the root partition to the RW mode;
• checking and connection of the file system (/image/root) of the working user data (the file "work");
• reflection of the modifiable directories of the PLC tree (/etc, /var, /root, /home, /mnt and /lib) to the file system with the user's working data (/image/root) through the file system "aufs" or "unionfs".

As the result of these actions the mount table of the resulting PLC tree looks like:
[root@localhost ~]# cat /etc/mtab rootfs / rootfs rw 0 0 udev /dev tmpfs rw,size=10240k,mode=755 0 0 /dev/hda1 /image vfat rw,fmask=0022,dmask=0022,codepage=cp866,iocharset=utf8,check=r 0 0 /dev/loop0 / squashfs ro 0 0 /proc /proc proc rw 0 0 sysfs /sys sysfs rw 0 0 tmpfs /tmp tmpfs rw 0 0 /dev/loop1 /image/root ext3 rw,noatime,nodiratime,errors=continue,data=ordered 0 0 /image/root/etc /etc unionfs rw,dirs=/image/root/etc=rw:/etc=ro 0 0 /image/root/var /var unionfs rw,dirs=/image/root/var=rw:/var=ro 0 0 /image/root/root /root unionfs rw,dirs=/image/root/root=rw:/root=ro 0 0 /image/root/home /home unionfs rw,dirs=/image/root/home=rw:/home=ro 0 0 /image/root/mnt /mnt unionfs rw,dirs=/image/root/mnt=rw:/mnt=ro 0 0 /image/root/lib /lib unionfs rw,dirs=/image/root/lib=rw:/lib=ro 0 0 devpts /dev/pts devpts rw,nosuid,noexec,gid=5,mode=620 0 0 shmfs /dev/shm tmpfs rw,nosuid 0 0

4.1.6. Setting of the GUI

One option of the firmware is built with a graphical interface, which, however, necessary to configure for automatic startup with the visualization area of OpenSCADA. In addition, it should be noted that the firmware with a graphical interface does not contain all the drivers and you may have to rebuild it under the right equipment.

After downloading and logging to the console it is necessary to configure the XServer, automatic graphical login, start of the graphical environment and automatic startup of OpenSCADA from the IceWM environment:
# XOrg configuration file downloading from ftp://ftp.oscada.org/OpenSCADA/PLC/xorg.conf, # placing it to folder /etc/X11 # !! File /etc/X11/xorg.conf edit to self needs. # Keyboard's layout switch adding for: English, Russian, Ukrainian $ echo "-option grp:lctrl_lshift_toggle -variant ,winkeys,winkeys -layout us,ru,ua -model pc104" > /etc/X11/xinit/Xkbmap # Test startup $ startx # Configuration of an automatic graphical login by creating the file /etc/sysconfig/autologin with the contents: $ echo "AUTOLOGIN=yes" > /etc/sysconfig/autologin $ echo "USER=admin" >> /etc/sysconfig/autologin $ echo "EXEC=/usr/bin/startx" >> /etc/sysconfig/autologin # Enabling, startup of the graphics at boot $ chkconfig dm on # Starting the graphics subsystem $ service dm start # !! Further actions are made in the terminal from the graphical interface # Creating the configuration file of automatic OpenSCADA startup from the IceWM $ mkdir ~/.icewm $ echo "#!/bin/sh" > ~/.icewm/startup $ echo "xset -dpms; xset s off" >> ~/.icewm/startup $ echo "/usr/bin/openscada_start" >> ~/.icewm/startup

4.1.7. Packages base of ALTLinux T6

Next stage of the firmwares creation was moving to the package base of distributive ALTLinux T6. On the whole firmwares creation concept saved, with bits changes, but there were added some improvements and expansions:

• Used the new function of "propagator" (the system of pre-initiation of hardware, searching and starting to the firmwares on FS) for searching/creation a partition of EXT2/3/4 with the label "alt-live-storage" for the "root" partition forming and it's modification possibility. The function provides a feature of installing packages direct from the distribution repository, and updating packages packed to the firmware, exclude the kernel and some system's services.
• Added the possibility of creation the firmware as combined ISO-image, which you can (besides it writing to CD/DVD) direct, at aid of the utility dd, write to USB-flash, HDD, SSD and get a work environment with the partition "alt-live-storage", the "root" reflection, on the storage's free place.
• For the possibility to creation of new firmwares to "LP-8x81" from ICP DAS was done moving the real-time kernel "rt-up" from the repository "ALTLinux 5.1" to "ALTLinux T6". The kernel "rt-up" was successfully adapted and get the working firmware based on the packages base "T6" for "LP-8x81".

During the possibility of a free additional installation of needs packages direct from the repository gone needs to the separated built of the firmware with GUI. That is you can easy install the desired window manager (WM) or desktop environment include needed drivers, than create a separated firmware with a limited list of the drivers.

The script "startup-plc" was turned spare into the new firmwares besides the "root" FS remounting to writing does early on the initial sage. The script "profiles/plс/image-scripts.d/01system" renamed to "profiles/plс/image-scripts.d/init1-PLC", but it changed and expanded. The packages list of the firmware was left into "profiles/pkg/lists/plс.in" and some changed.

For get the some specific packages you have to connect the repository "ALTLinux T6" from the OpenSCADA project:

The firmware creation procedure mostly left unchanged:

The output folder's content with the image and the firmware installing process to file system FAT and EXT2/3/4 different only by renaming the FS archive's file from "plc" to "live". Installing the ISO-image to USB-flash, HDD, SSD performs by the command dd:

Instead the file "work" you should create partition EXT3 with the label "alt-live-storage", if it is not the ISO-image. The new partition creation you can do with the help of fdisk, if the FAT partition was not created to all allowed the storage space, or with help of parted where the FAT partition you allowed to change. To the details about a partition creation the reader will send to the documentation on fdisk or parted.

Configuration of files "syslinux/syslinux.cfg" and "extlinux/extlinux.conf" were not changed, besides the FS file archive's name changed from "plc" to "live".

At the result we get the firmware with size from which provides:

• Loading for 25 seconds from the controller's switch on and including the initialization of BIOS.
• Checking and restoration of the journal of the working file system "root" into "alt-live-storage".
• Storing the user data and changes of the firmware, also new and updated packages, in the partition "alt-live-storage".
• Automatic network configuration with DHCP (or 192.168.0.1), for the first interface.
• Access to the controller via SSH and user-friendly interface of working, including mc. The passwords by default omit and the user "root" allowed for connection to it via SSH.
• Time synchronization via NTP.
• OpenSCADA execution with the available network interfaces:
  • configuration and runtime environment via Web (ports: 10002 and 10004);
  • control interface of OpenSCADA (10005).

For the PLC firmware assembling used next packages list:
# INIT 3 # acl usbutils screen acpid acpi anacron vim-minimal mc sound-scripts alsa-utils apt udev udev-initramfs dbus schedutils pciutils setserial lm_sensors3 rsync interactivesystem su system-report mtools netcat strace binutils syslogd glibc-utils glibc-gconv-modules glibc-nss glibc-timezones glibc-locales shadow-utils keyutils lsof sudo # INIT3: BLOCK DEVICES # hdparm fdisk ms-sys syslinux dosfstools e2fsprogs #network etcnet dhcpcd xinetd iftop lftp wget iptables ntp ntpd ntpdate tcpdump multipath-tools openssh-clients openssh-server ppp-pppoe #### LP kernel-modules-icp-@KERNEL_MOD@ #### Console OpenSCADA libgd2-noxpm openscada-plc openscada-DAQ.DiamondBoards openscada-DAQ.ICP_DAS openscada-DAQ.Comedi

The Linux kernel modules list of the initial stage was some changed and include:
loop.ko mtouch.ko pcmcia_core.ko rsrc_nonstatic.ko yenta_socket.ko scsi_mod.ko libusual.ko ide-disk.ko ide-core.ko ide-gd_mod.ko sd_mod.ko usbcore.ko ehci-hcd.ko ohci-hcd.ko uhci-hcd.ko appletouch.ko usbhid.ko usbtest.ko usb-storage.ko mbcache.ko jbd.ko ext2.ko ext3.ko fat.ko nls_base.ko nls_cp866.ko nls_koi8-r.ko nls_utf8.ko zlib_inflate.ko squashfs.ko unionfs.ko aufs.ko vfat.ko pata_via.ko pata_cs5536.ko amd74xx.ko

To the script of the tree preparation "profiles/plс/image-scripts.d/init1-PLC" performs the functions:

• changing the name of the distribution kit;
• enabling login from the user "root" via SSH, without a password;
• setting locale to "en_US.UTF-8";
• network configuration for use DHCP or set to "192.168.0.1" for the first interface;
• clock setting on the whole and the time-zone setting to "/usr/share/zoneinfo/Europe/Kiev", for changing what you need replace the file "/etc/localtime" to need zone;
• enabling of the necessary services;
• removing of the documentations, help pages and information, icons;
• removing of the not needed locales and the translations; left for presence only the locales: en_US, uk_UA and ru_RU;
• selection of only used kernel modules and deletion all the others is added; it is disabled by default and can be enabled to preparation the final firmware for specific equipment; it was unified for the modules list setting by groups of the kernel subsystem’s and specified for hardware;
• the directory with the kernel (/ boot) is deleted in connection with its moving to the root of the boot partition.

4.1.8. Real-time kernel

For a series of tasks are important, often also critical, criteria of the environment is the real-time handing level, then it is possibility of working the tasks according to the real-time priorities and provision of a reaction to events by that priorities.

The Linux kernel of itself provides POSIX real-time scheduling policies "SCHED_FIFO" and "SCHED_RR" with the priorities range (0...100). But the important criteria is "Timer frequency and the reaction to it" up to version of Linux kernel 2.6.24 was too low, for criteria of the real-time systems. In modern kernels of Linux (> 2.6.24) provided support for timers of the high-precision resolution (HPET), what decreased the reaction time to a timer up to 100 microseconds, but that time stability is not guaranteed. To ensure stability of reaction to a timer on level 60 microseconds, and also series of the other criteria of real-time, at the moment you need to assemble a kernel with one real-time extension.

On the ALTLinux distributions observed the kernel 2.6.29-rt-up, which assembled with the real-time extension of real-time is XENOMAI. Into other distributions, for example OpenSuSE, observed also the solutions with it extension.

For now higher criteria of the real-time ensured of the extension The Real Time Preempt Patch, on enabling here full it's features by (CONFIG_PREEMPT_RT), The patch assembling to Linux kernels process and it's work result will trace into this section.

For the real-time level testing on different kernels will use the utility "Cyclictest", which typical call command line and it's arguments looks: "$ cyclictest -t1 -c1 -p 80 -n -i 200 -l 100000". Where:

• -t1 — single testing thread;
• -с1 — using the clock of real-time CLOCK_REALTIME;
• -p 80 — priority of the testing thread;
• -n — using the function "clock_nanosleep";
• -i 200 — pulling interval of the testing thread: 200 us, as closer to the average value 50 us;
• -l 100000 — testing iterations number.

Pair of measurements for Linux kernels of the wide purpose:

• ALTLinux T6 distribution standard kernel (3.0.79-std-def, LP8781):
  • loading 0%: Avg: 37 us; Max: 152 us
  • loading 100%: Avg: 37 us; Max: 191 us
• ALTLinux T6 distribution kernel (3.4.45-un-def, LP8781):
  • loading 0%: Avg: 53 us; Max: 217 us
  • loading 100%: Avg: 40 us; Max: 183 us

4.1.8.1. kernel-image-rt-up-2.6.29

The kernel originally presents into the distribution ALTLinux 5.1, and it is also moved to the local repository of the project OpenSCADA for ALTLinux T6. The kernel assembled with the extension XENOMAI and AUFS, allowing it using into the firmwares and packed root FS, that was done for the PLC LP-8x81.

Results of the kernel testings:

• LP8781 (XENOMAI)
  • loading 0%: Avg: 26 us; Max: 136 us (there observed jumps up to 1 ms, like to instability the source clock "tsc", at that the "acpi_pm" worse here)
  • loading 100%: Avg: 24 us; Max: 3655 us
• LP8781 (CONFIG_PREEMPT_NONE)
  • loading 0%: Avg: 29 us; Max: 71 us
  • loading 100%: Avg: 28 us; Max: 117 us (there observed jumps to continuous the measured value rising)
• LP8781 (CONFIG_PREEMPT_RT)
  • loading 0%: Avg: 29 us; Max: 64 us
  • loading 100%: Avg: 29 us; Max: 82 us
• AMD Turion Neo X2 L625 (CONFIG_PREEMPT_RT)
  • loading 0%: Avg: 57 us; Max: 74 us
  • loading 100%: Avg: 57 us; Max: 78 us

As you can see from the testing results the patch XENOMAI does not ensure proper level of the real-time on using the standard mechanisms of the POSIX real-time scheduling, at the same time as the kernel version 3 even without the specific real-time extensions ensures the clearly better result.

Necessity for assembling same that kernel with the patch/parameter CONFIG_PREEMPT_RT is actual by presence a number of binary modules from ICP_DAS, for "LP8x81". Also here is actual a question of building the kernel 2.6.33 at the same reasons but for "LP8x81 Atom". The preliminary assemblies of the kernels 2.6.29 and 2.6.33 reveals series of problems which will described here. Solving also a variant to build a modern kernel with CONFIG_PREEMPT_RT and next to request for building these binary modules from "ICP DAS".

Assembling and testing process:

1. Patches CONFIG_PREEMPT_RT and AUFS of days of 2.6.29 are conflict on the function "debug_mutex_set_owner()", into CONFIG_PREEMPT_RT it removed — replaced to "mutex_set_owner()".
2. On the assembling here detected series of problems for "# typedef void irqreturn_t;" — replaced to "#include <linux/irqreturn.h>".
3. The first start with CONFIG_PREEMPT_RT, but without AUFS, was successful — the results above.
4. The starting with AUFS was reveal a problem into memory allocation by AUFS into "aufs_mmap()" — the working code of AUFS was taken from the preliminary assembling "rt-up-2.6.29.alt2".
5. It starting with AUFS was reveal a problem of hanging on the FS root into AUFS, like to possibility of cycling/blocking a RT-task — setup CONFIG_PREEMPT_NONE, on LP8781 and "AMD Turion" any problem does not observed (possible the problem due the HPET missing on PLX8).
6. At the first look the kernel works fine, but observed jump to continuous growing the measured value of the delay time.
7. There finished adapting of the kernel to a binary compatibility for the modules "slot" and "icp" from ICP_DAS. The module "8250_linpac" crashes at it's loading, and "icpdas_8250" has more unresolved symbols — the modules need to reassemble or to try the interfaces > COM2 initiate through setserial — the modules was reassembled by the help of Golden Wang (technical support of ICPDAS).
8. The new kernel set to high loading by the project configuration ACS ball drum mills:
   • network with the driver "via_rhine" halted, after 4 days of successful working — the halt expected, assembled the driver "rhinefet", testing continued.
   • on the driver "rhinefet" the system on loading had work three weeks. But here observed the interrupt 11, on what hangs mostly all standard hardware (USB, Ethernet and may be something), had disabled and the network continued to work into "Pool" mode, which is slower. Possible that interruption disabling occurs also with "via_rhine", and it can not work in the mode "Pool", why packages into the network do not go. The problem reason linked to halt and generation the unhandled interruptions from one of hardware on the interruption 11.
   • The problem fixed by preventing the interruption disabling at help the Linux kernel parameter "noirqdebug".
   • The adapting successful finished and the firmwares based on the kernel ready to the production implementation!
   • 01.03.2015: Instead function EnableWDT() used EnableSysWDT(), by limit to 30 seconds and cyclic reloading if the system was not loaded in 30 seconds (up to three reloadings).
   • 17.03.2015: With assist the ICP_DAS support service was fixed a problem into the serial interfaces driver for more to COM2 which causes to Linux kernel "freeze" (like to interruptions block) after closing one port and activity on some other.
   • 29.07.2015: Detected one more problem looks like by the symptoms to the interruption 11 disabling, but: the interruption 11 is not disabled and all other devices on it works. It reproduced only on configurations with using that both network interfaces, at that possible "braking" for one of its. The problem resolved only by reloading "the braked" network interface, by the command: ifdown eth0; ifup eth0. To detect it and the reloading performs we recommend on the OpenSCADA level append the traffic control and same reloading of the interface on the traffic lack.
   • 21.11.2016: Driver "rhinefet" has been adapted to prevent the interrupts lock and the interrupt vector disable but SHARE mode using. For now it works but 19.12.2016 also there was observer the two adapters network slowing after about two week working.
   Then the hardware is broken for two adapters work and for the PLC you can use only one for stable work!

Result kernel, which renamed to "kernel-image-rt1-up-2.6.29.alt1", you can use for PLC with HPET or a high precision timer, and also into "LP-8x81" and "LP-8x81 Atom" (only single kernel)!

4.1.8.2. kernel-image-rt-up-2.6.33

Kernel version 2.6.33 assembling with the patch CONFIG_PREEMPT_RT needs for PLC LP-8x81 of firm "ICP DAS" and LP-8x81 Atom (main and original kernel) by reason of presence for it the binary drivers of "ICP DAS".

Testings results of the kernel:

• AMD Turion Neo X2 L625
  • loading 0%: Avg: 65 us; Max: 86 us
  • loading 100%: Avg: 57 us; Max: 72 us
• LP8781
  • loading 0%: Avg: 37 us; Max: 88 us
  • loading 100%: Avg: 34 us; Max: 108 us
• LP8781-Atom (original assembling of the kernel 2.6.33.7-rt29-ICPDAS)
  • loading 0%: Avg: 17 us; Max: 50 us
  • loading 100%: Avg: 12 us; Max: 32 us

Assembling and testing process:

1. Assembling of the kernel from sources of "ICP DAS" (2.6.33.7) and configuration it inherited from kernel 2.6.29 (the source code has suspiciously more of *.rej files, and also "staging/comedi" impossible to build) — it started and mostly works; modules "ipic" and "slot" loaded; module "8250_linpac" crashes into function "platform_device_add"; series of programs hangs into FS operations, with the message: "task openscada:2153 blocked for more than 120 seconds".
2. AUFS replacing to the version from 2.6.29-rt1 — crashes into rtmutex on starting; replacing to official version from git looks same result, at the begin used patch "aufs+sqfs4lzma-2.6.33.patch" from DLink.
3. Assembling the original kernel with patches CONFIG_PREEMPT and AUFS — a problem again into AUFS, but now it at the finish can not look "/sbin/mingetty".
4. Assembling the original kernel 2.6.33.9 with patches CONFIG_PREEMPT and AUFS — same problems.
5. Assembling from sources of "ICP DAS" (2.6.33.7) for SMP — the module DAQ.JavaLikeCalc of OpenSCADA crashes at an unknown reason.
6. Assembling the original kernel with patches CONFIG_PREEMPT and AUFS for SMP — same problem as without SMP but it is not immediately and about five thread.

For now the kernel 2.6.33 links with CONFIG_PREEMPT_RT and AUFS is non-working. Then if you need to work on "LP-8x81 Atom" then we recommend to use the original Linux-environment, building and installing the OpenSCADA here.

4.2. Diamond Systems ATH400, DMM32

The boards from "Diamond Systems" were a first on which OpenSCADA had tested and stabilized. First board here was single-board computer ATH400 of the form-factor PC/104, shown on the image bottom. On the computer a OS environment early was installing in traditional method and for now by the presented conception of the firmwares assembling.

Hardware specification of the board:

First task of the board and OpenSCADA was implementation of function of high-frequented (10 kHz * 8 channels) signals archiving of a gas compressor for learning the surge phenomenon on Anastasievskaja GLKS.

Second task was the PLC prototype of power substations nodes. Already for this task the firmware had assembled on base of new package base. Into the task Data acquisition module of boards of the "Diamon Boards" was unified for support all boards of the manufacturer.

Second board was one board of the interface to the object DMM32-AT, shown on the image bottom. The board used for creation of mockups and emulators of field of technological programs. The board has specification:

Analysis of noise properties of high-impedance inputs of boards from Diamond Systems in different conditions placed to table bottom:

4.3. Kontron MOPSlcdLX

MOPSlcdLX is single-board computer of form-factor PC/104, shown on the image bottom. The computer had attracted attention by some low price, by ordinal conditions of the exploitation and then lower heating.

Hardware specification of the board:

The board had used for testing of creation operator stations/panels with OpenSCADA into like environment. Latter there had occur problems series with the board:

• The clock's battery lack then it needs to setting the time at any starting or setting the external battery. At that the BIOS settings stored not in CMOS but in FLASH, it is kind good but if the BIOS configuration reset impossible then it is too bad.
• A problem into the interruption scheme which cause to block all or mostly adjacent interruptions at the module "geode_aes" loading.
• In some time the video-card or it's video-output burned but the configurations of BIOS stored into FLASH and there impossible to return its, for fix possible disabled the video into the BIOS. Also the BIOS do not support of forwarding self interface to a COM-port. Will try use CRT here, when it emerged.
• The high-precision counter (HPET) lack, that surprisingly and make this board unusable for real-time systems but ordinal counter can provide lag about 4ms.

For now base on this board preparing "The program oscilloscope" why it was successfully downloaded by the modern firmware with kernel "std-def" and addition board DMM-32X-AT installed, about that see above.

4.4. Tri-M VSX104

VSX104 is single-board computer of form-factor PC/104, sown in the image below. The computer had attracted attention by the reason of low price and low power consumption (< 2W) and followed low heating. But by using the processor "Vortex86SX-300 МГц" here needs specific points to forming of the OS environment, but here used CPU instructions set of i486 and the mathematical coprocessor lack.

Hardware specification of the board:

For now there is not a solution based on the board but planed to assemble for it a environment, possible for an autonomous control resources system.

Force redirection of the BIOS interface to a COM-port possible to enable by grounding the 10 pin of the COM-port.

4.5. ICOP VDX-6354D

VDX-6354D is single-board computer of form-factor PC/104, sown in the image below. The computer builds on the processor "DM&P SoC CPU Vortex86DX- 800MHz", which more productive to "Vortex86SX-300 МГц" into above section, but the power consumption for this board already not 2 but 4 Watts see details on the project page (RU).

4.6. ICP DAS LP-8x81

Industrial controllers of family LP-8x81 of firm ICP DAS are a first product from series LinPAC built on x86 compatibility processor, early created controllers of this family based on processors of ARM family. Besides the x86 processor these controllers have significant resources of the operative memory and main storage's space. All that had allowed see to the controller as first candidate from products of ICP DAS for OpenSCADA adapting as environment of execution see details on the project page.

4.7. Avalue Sensor panel FPC-1701

Firm Avalue in accordance with Russian firm ElTech provide wide range of panel PC which you can use starting from ordinal mono-blocks and ending by industrial sensor panels into the frontal protection class IP65. By a standard hardware using here you can start and work in OpenSCADA without a problem see details on the project page (RU).

4.8. iROBO-3000a

iROBO-3000a is a fanless industrial computer with Intel Atom D425 1.8 GHz with VGA, 2xGb LAN, 4xCOM, 4xUSB, 1GB RAM, 1x2.5" SATA HDD 120GB, Mini-PCIe, 4x4 DIO, CF slot, SIM Card slot, Audio, WDT on board, operating temperature range -5...+55°C. Performance of this computer is enough to run the functions of data acquisition, monitoring and control server, as well as the visualization station's functions. However, because of usage the non-productive Atom processor family, the implementation of mathematical models of processes will require almost all of the CPU resources. For example, during the performance of the AGLKS mathematical model, the CPU is loaded at 86%. The controller has been certified by "UKRSEPRO" that may be important for many users in the territory of Ukraine.

OpenSCADA operating environment for this computer was based on the packets base of the ALTLinux T6 distribution, as well as freshly-builded Trinity (TDE) desktop environment. Building of the environment was made using the above described conception with an updated profile of "mkimage". The "plc" objective has been added to the new profile, but its nature has changed in fact and has become a copy of the "live" target, which became possible thanks to the implementation in primary initialization stage the transparent mount of the partition with the "alt-live-storage" label as a reflection of a packed file system with random access to the modification. In general, it made possible to create the fixed core of the firmware with the basic set of software environment with the size of 300MB and with the possibility of free expansion by installing the necessary packages from the distribution.

The Trinity was selected as the desktop environment because of the presence of background artefacts problem in conjunction with XOrgServer 1.10 + Qt4, as well as because of TDE low-resource with high maturity and stability.

Archive of the build profiles of the new environment is called mkimage-profiles-6-kdesktop-plc.tgz, and the latest build of the firmware ALTLinux_6-OpenSCADA_0.8.1-TDE_3.5.13.1-i586-flash.tar.

4.9. Advantech PCA-6753, PPC-L126

Firm Advantech produces wide range of hardware for automation, start from panel PC and finish data acquisition modules ADAM.

In the project Data acquisition system of boiler №1 CHP (RU) to hands we get panel PC PPC-L126 and industrial PC on chassis IPC-6608 with processor board PCA-6753.

The industrial PC "PCA-6753" has next specification:

The controller is some old and has a low-performance for modern programs but for the tasks of execution environments of PLC it is suitable enough and on it was successfully downloaded firmware based on ALTLinux 5.1 packages base. At that about a real-time no a speech was by the high-precision timer (HPET) lack.

The panel PC "PPC-L126" has next specification:

The panel PC also has small resources for start modern environment then for installing on it was using the distribution "ALTLinux T6" with the actions to optimization:

• storage drive performance — for the data storage used the IDE hard-drive which ensure 10 MB/s, more then allowed CompactFlash;
• all spare services disable;
• the desktop environment TDE usage as lesser demanded to resources but more advanced; into the reserve has IceWM;
• building OpenSCADA without libraries Phonon and WebKit which too demanded to resources.

These actions allow fit the system to 128 MB of operational memory and get at that an advanced and productivity graphical environment. For the sensor display ELO configuration had using the driver "elographics" — "xorg-drv-elographics". To the configuration file "xorg.conf" added section:
Section "InputDevice" Identifier "ELO touchscreen" Driver "elographics" Option "Device" "/dev/ttyS3" Option "MinX" "300" Option "MaxX" "3800" Option "MinY" "3800" Option "MaxY" "300" Option "UntouchDelay" "10" Option "ReportDelay" "10" Option "SendCoreEvents" "yes" Option "ScreenNumber" "0" Option "ButtonNumber" "1" EndSection

5. Firmware and creation of the PLC software environment for the ARM architecture

Widespread in embedded solutions the ARM architecture obtained due to its relatively high productivity coupled with low power consumption and cost. In order to perform planed task to provide the hardware multiplatform the OpenSCADA system was adapted to the building and operation on the equipment of ARM-architecture. Thus, the following projects were made Building the OpenSCADA project for the mobile devices of the Nokia company (N800, N900, N950) and Building the OpenSCADA and firmware for the ARM-based controllers from ICP DAS (LP-5141). The purpose of this section is to systematize the procedures and track he problems of creating the OpenSCADA buildings and software environment firmwares as a whole for a variety of embedded ARM-architecture hardware.

Specific of the ARM architecture is the lack of a necessarily hardware-dependent software system of the basic initialization and configuration of equipment, which is characteristic for the x86 architecture — BIOS, and the structure of hardware configuration typically includes: CPU, integrated operational and flash memory, as well as a number of built-in equipment on a standard system-level buses. The flash and RAM are placed in general address segment. Initialization of the such system with the software environment is made by downloading executable code directly on the built-in flash-memory.

To working of computing functions of OpenSCADA and other related libraries and softwares the performance of floating point calculations is very important. Specific of the ARM architecture processors is the ease of its core and availability of optional extensions such as math coprocessor. As a consequence, the performance on floating point operations is highly dependent on the specific processor, and on the emulation type of the floating point coprocessor if it is absent at all. There are two formats of floating point in the ARM-architecture processors: FPA and VFP. FPA format is obsoleted and met as a hardware implementation in the ARM cores up to the StrongARM family (ARMv4). XScale ARM core families (ARMv5TE) did not have a math coprocessor at all. And the ARM core, starting with the ARM11 family (ARMv6) are equipped with VFP format math coprocessor. At the same time the ARM processors with the ARMv5 architecture are still widespread, and thus the question of performance of mathematical calculations for them comes down to the performance of the FPA or VFP format emulation. In the case of the Linux environment the emulation of FPA is usually done by the Linux kernel by the CPU exceptions handling when calling FPA commands. Software emulation in the math library is usually found with the VFP format which requires the rebuilding of all programs. The FPA emulation by means of exceptions is much worse than the performance of software VFP emulation. You can compare the performance of floating-point calculations on different architectures, processors and ways of emulation in appendix 1.

The typical software environment based on the Linux operating system for ARM based hardware is: Loader UBoot, Linux kernel and root file system (RFS). UBoot loader is loaded into the zero sector of flash memory, and its settings are stored in the first one. From the second sector the kernel code is loaded, and immediately after it - the RFS. RFS is usually uses as basis the JFFS2 or UbiFS file system, which are optimized to work on block devices — flash memory with a limited resource of records. Examples of partitioning a block device (flash memory) for LP-5141 and TionPro270 are presented below:
# LP-5141 $ cat /proc/mtd dev: size erasesize name mtd0: 00040000 00020000 "Bootloader" mtd1: 00040000 00020000 "Bootloader Param" mtd2: 00280000 00080000 "Kernel" mtd3: 03c80000 00080000 "JFFS2 Filesystem" # TionPro270 $ cat /proc/mtd dev: size erasesize name mtd0: 00080000 00040000 "Bootloader" mtd1: 00400000 00040000 "Kernel" mtd2: 01b80000 00040000 "Filesystem"

The root file-system contains a typical UNIX-tree with work programs, libraries and other files. The basis of any program or library are the system libraries GLibC or UClibC. OpenSCADA is adapted for building and operating with "GLibC" version >= 2.3. "UClibC", created as a lightweight version of "GLibC" for embedded systems, contains a number of limitations and has not yet been implemented or has errors in the implementation of a number of functions.

RFS and a software environment based on Linux can be supplied with the ARM-equipment and contain closed binary libraries, Linux kernel modules, etc. In this case, an independent building and replacement of the original software environment is impractical task because it leads to the loss of original functionality. However, it often happens the delivery of the ARM equipment without the source (original) software environment, or with an environment that does not contain closed code and which can be replaced. An example of the first case is the controller LP-5141 and similar of the "ICP DAS" company, which contain the binary building of the specialized equipment API library (libi8k) and Linux kernel modules for its initialization. An example of the second case is a single board computer Chion-Pro270, the software environment creating and OpenSCADA building for the ARM architecture of which will be considered below.

5.1. Building tools for the Linux kernel and working environments for different target architectures

Linux RFS can be formed on the basis of ready packages of the existing binary distribution, source package of the current distribution, as well as to build from the original sources through the ToolChain in one of the building systems.

Building of the programs or of an entire RFS for architectures other than x86 and x86_64, is usually made using the Cross Compilation tools (ToolChain) for building, linking and debugging for the target ARM architecture. To automate this process a number of tools to build the ready RFS created.

5.1.1. BuildRoot

This building system is a part of the project for creation an alternative library of functions of "C" language UClibC, so basically aims to build environments with "UClibC", and with appropriate restrictions. BuildRoot is well in the work on the host systems of different versions, and allows to build the software environments based on Linux without too much troubles.

It is possible to get the BuildRoot archive of the correct version by the link http://buildroot.uclibc.org/downloads. Further it should be unpacked to the home directory of the simple user and the configuration, setup and building should be done:
# Initial configuration relative to the previous one, for example after changing the BuildRoot version $ make oldconfig # Configuration from the character graphics menu $ make menuconfig # Starting the build $ make # Entire cleaning the build environment $ make distclean

The build process can cause following problems:

• Inability to download the programs archive.

• Programs' building errors.

5.1.2. PTXDist

Universal tool fro the building of kernel's, ToolChain and software environments based on Linux from the "Pengutronix" company. PTXDist is a powerful and flexible tool, but it's older versions have problems in the modern host systems, which complicates the task of building the software environments for relatively old but still prevalent hardware platforms. For example, now (2012) can be found new hardware with the ARM XScale, ARM9 (ARMv5) processors of the 2003 year. However, newer versions of PTXDist support the old platforms, what can be learned from the support table by the link: http://www.pengutronix.de/oselas/toolchain/index_en.html.

To build the software environment (RFS) using PTXDist it is necessary:

• to get the builder's tool archive (along with the next versions projects, http://www.pengutronix.de/software/ptxdist/download), compile and install it;
• to get archive of source files (the same or similar version as PTXDist, http://www.oselas.com/oselas/toolchain/download) and build ToolChain;
• to clone-create and build the RFS project.

Now detailed, in commands:
# Installation and building of the builder must be done from the simple user in his home directory. # The source archives are loaded to the ~/Downloads $ mkdir ~/proj/ptxdist; cd ~/proj/ptxdist $ tar xvjf ~/Downloads/ptxdist-2011.11.0.tar.bz2 $ tar xvzf ~/Downloads/ptxdist-2011.01.0-projects.tgz # Transfer the contents of the projects' archive to the working version's directory, if the versions are different. $ cp -r ptxdist-2011.01.0/* ptxdist-2011.11.0/; rm -rf ptxdist-2011.01.0 # Building and installation of the toolkit $ cd ptxdist-2011.11.0; ./configure --prefix=/home/roman/proj/ptxdist; make install # Setting the environment variable "PATH" to call the toolkit file "ptxdist" $ export PATH=$PATH:/home/roman/proj/ptxdist/bin # Unpacking, configuration and build the Toolchain $ cd ~/proj; tar xvjf OSELAS.Toolchain-2011.11.0.tar.bz2 # Select the desired configuration of toolchain $ cd OSELAS.Toolchain-2011.11.0 $ ptxdist select ptxconfigs/arm-xscale-linux-gnueabi_gcc-4.6.2_glibc-2.14.1_binutils-2.21.1a_kernel-2.6.39-sanitized.ptxconfig # Start of building the ToolChain. # Build result will be placed in the directory /opt/OSELAS.Toolchain-2011.11.0, you need to give full access from the root to the directory /opt. $ sudo chmod a+rwX /opt $ ptxdist go # Cloning-creation of the RFS project # Presetting of the general configuration of ptxdist, for example, the path to a directory of projects (is not required by defaults) $ ptxdist setup # Checking for availability and visibility of the projects to clone $ ptxdist projects # Cloning the one of the available projects $ cd ~/proj; ptxdist clone OSELAS.BSP-Pengutronix-Generic New_RootFS # Choice to a platform configuration and the previously built ToolChain for this project $ cd ~/proj/New_RootFS $ ptxdist platform configs/arm-qemu-2011.01.0/platformconfig $ ptxdist toolchain /opt/OSELAS.Toolchain-2011.11.0/arm-xscale-linux-gnueabi/gcc-4.5.2-glibc-2.14.1-binutils-2.21.1a-kernel-2.6.30.5-sanitized/bin # Other settings of the architecture, programs selection and formation of the result are configured into the pseudographics configurator $ ptxdist menuconfig # Building of the RFS and the formation of images $ ptxdist go $ ptxdist images # Additional programs configuration of the building should be placed in directory "rules" as two files: pkg.in and pkg.make. # For a new program to be appeared in the menu of pseudographics configurator, it must be added # to the file ~/proj/ptxdist/lib/ptxdist-2011.11.0/rules/Kconfig

5.2. Tion-Pro270

Single-Board Computer "Tion-Pro270" is a highly integrated computational-control system, based on the Marvell PXA270 processor with XScale ARM core from the ZEO company. This card was given to the developers of the OpenSCADA project by the Alex Popkov in order to adapt OpenSCADA for it.

All materials on building the programming environment with OpenSCADA and ready builds for Tion-Pro270 board can be obtained at: ftp://ftp.oscada.org/OpenSCADA/PLC/TionPro270

The board is supplied by the equipment manufacturer with preinstalled software environment based on Linux™ or Windows CE©. Besides all the source materials of the software environments are available in Wiki-resource of the manufacturer.

We got the board with the minimal software environment for which it was not possible to build OpenSCADA, so the new software environment has been fully loaded to the board. Download the software environment to the flash-memory was made with the help of JTAG-adapter OLIMEX ARM-USB-OCD and OpenOCD program of version 0.5.0, building of which should be configured with the "--enable-ft2232_libftdi" parameter.

For downloading to board's flash memory it was used ready boot buildings UBoot-1.3.3 (file of the image is u-boot-1.3.3_svn886_520mhz_tion_pro270_64m.bin) and kernel Linux-2.6.22.19. JFFS2 RFS filesystem image was built with the help of "BuildRoot" and "PTXDist", see below.

Flashing of the equipment with help of "OpenOCD" was made from root by the following command:

"tion270.cfg" script of the flash and image files of the software environment specified in the flash script "tion270.cfg", should be placed in the current directory. The flash script "tion270.cfg" includes:
# Tion270 and Tion-Pro270 Openocd config set CHIPNAME tion270 source [find target/pxa270.cfg] jtag_khz 2000 jtag_nsrst_delay 10 jtag_ntrst_delay 10 reset_config trst_and_srst separate # Works for J3, P33 flash # flash bank <name> <driver> <base> <size> <chip_width> <bus_width> flash bank 0 cfi 0x0 0x2000000 2 4 $_TARGETNAME init reset halt flash probe 0 flash protect 0 0 1 off flash erase_sector 0 0 2 puts "(1/3) Flashing u-boot ..." flash write_image u-boot-1.3.3_svn886_520mhz_tion_pro270_64m.bin puts "(2/3) Flashing linux kernel image ..." flash write_image erase uImage-2.6.22.19_svn818_tion-pro270_eabi 0x00080000 puts "(3/3) Flashing root filesystem ..." flash erase_sector 0 17 127 flash write_image rootfs_TionPro270_buildroot.jffs2 0x00480000

5.2.1. Building of the RFS in the BuildRoot

In order to avoid multiple build problems associated with the build from the beginning, the configuration "buildroot-2009.08" was taken directly from the Git-repository of the equipment manufacturer: http://zao-zeo.ru/media/files/linux/buildroot-2009.08.git. In order to build in the "BuildRoot" environment the configurations were created in the directory "./package/" for the "LibGD" library and OpenSCADA.

Result RFS was loaded to the flash memory of the board and started successfully. However, at start it became clear that the "uCLibs" version 0.9.30.3 does not implement the function clock_nanosleep(), as well as crashes in the function timer_settime() for the type of notification SIGEV_THREAD. The the clock_nanosleep() function can be replaced by nanosleep(), but it is impossible to solve the problem of the timer_settime() function within this version of "uCLibs".

Next, an image of the current version of the "BuildRoot" on 16.01.2012 was taken, and the building of OpenSCADA with "uCLibs" version 0.9.32.1 were made. The building was successful after some adaptation of the building environment. OpenSCADA started successfully with some problems that have been resolved.

Following list describes problems encountered during building and operation of OpenSCADA on uCLibC of different versions:

• There is no implementation of the usleep() and msleep() functions in the typical configuration — it is created and widely used the system-wide function for OpenSCADA sysSleep() with the implementation based on nanosleep().
• < 0.9.32: it can't be built due to the lack of a number of functions, as well as OpenSCADA can't start:

• 0.9.32: building was done successful, with some solved problems when starting the OpenSCADA:

5.2.2. RFS build in the PTXDist

Learning the PTXDist for building environment on TionPro270 was made using the experience of the following link http://www.emb-linux.narod.ru/tion-pro-270/index.html. However, the article was written a long time ago and it was used the ptxdist-1.1.1 version for building, which actually doesn't work on the modern software environments, and also part of the libraries needed for OpenSCADA can't be built there easy. At end it was based on version ptxdist-2011.11.0 and the building was made using this version.

Before the building of RFS the ToolChain configuration for this board was created arm-xscale-linux-gnueabi_tion270.ptxconfig on the basis of the existing arm-xscale-linux-gnueabi_gcc-4.6.2_glibc-2.14.1_binutils-2.21.1a_kernel-2.6.39-sanitized.ptxconfig with the following programs' versions:

• GLIBC_ENABLE_KERNEL="2.6.19", because the actual kernel is 2.6.22 version, and to work with him GLibC should be given less than or equal version;
• KERNEL_HEADERS_VERSION="2.6.30.5", kernel version for the headers;
• CROSS_GCC_VERSION="4.5.2".

Next was created PTXDist "OSELAS.BSP-Pengutronix-Generic" project's clone in directory "TionPro270_RootFS" with the configuration platform "arm-qemu-2011.01.0". To build OpenSCADA following configuration files was created openscada.in and openscada.make, which were placed in the local configuration directory of the project rules/. It was adapted the configuration of the udev program, which version was very big for the original version of the kernel Linux-2.6.22, ie it was used the udev of 141 version. New configuration files of udev were also placed in the directory rules/, thus defining their usage instead of the original configuration.

The RFS was successfully built and jffs2 image of FS was received. The resulting RFS was successfully loaded onto the board and started. OpenSCADA started and work correctly as well.

5.2.3. Adaptation

This board contains a number of hardware interfaces interesting to adaptation for OpenSCADA, so this section will be focused on the adapting process.

The board contains a chip converting signal levels from RS232 to RS485, which, however, is not clear to send requests from the software. Namely:

• to send a request you need to set the RS232 interface signal "RTS" at zero;
• it is necessary to read interface for waiting the echo package of the request, after receiving of which the RS232 signal "RTS" should be set to true, the echo package should be dropped and then you should waiting for direct response.

To the specific solve the OpenSCADA module Transport.Serial has been improved for this kind of hardware flow control support.

Using this extension, validation was made and presence of LP-5141 controller's software environment problem was confirmed.

5.3. ICP DAS LP-51xx

Firm ICP_DAS long enough releases controllers on processors the ARM architecture within preinstalled OS Linux environment, as into the LP-5141 variant, that makes interesting to creation an assembling or a new firmware with OpenSCADA details on the project page.

5.4. Nokia N800, N900, N950, N9

Firm Nokia is one of worldwide leaders into manufacturing and marketing of mobile telephones. Into year 2005 the firm Nokia released the pocket personal computer (PPC) N770 based on featured Linux environment with proper environment of desktop (on GTK+) — Hildon with main the project name Maemo. Later base on the platform Maemo was released yet three mobile devices — two PPC "internet-tablet" N800, N810 and smart-phone "internet-tablet" N900. In 2010 the firm Nokia joined forces to work on the Maemo with the project MobLin of firm Intel, creation the project MeeGo. On the platform MeeGo in 2011 year was released two smartphones N950(prototype) and N9, details on the project page.

5.5. SMH2Gi

Freely programmable panel controller "SMH2Gi" is a highly integrated computational control system with the iMx27 processor based on the ARM926EJ-S core of the Segnetics company. Adaptation and building of the OpenSCADA for this controller was needed as part of the Automated control system for the vacuum process unit project.

All materials on building the programming environment with OpenSCADA and ready builds for the panel controller can be obtained at the link: ftp://ftp.oscada.org/OpenSCADA/PLC/Segnetics-SMH2Gi.

The panel controller is supplied by the equipment manufacturer with preinstalled environment based on Linux™, and its own runtime of the controller - "SMLogix". The role of OpenSCADA for this controller was seen as enhanced programming environment of the controller, integrated and programmed from the top level station on the basis of OpenSCADA. To preserve the possibility of visualization and control of data obtained in OpenSCADA on the integrated display, while minimizing the effort required for the adaptation, it was decided to save the original runtime environment "SMLogix" for the task of data visualization on the internal display, and to transmit data to/from it via a local ModBus/TCP connection. Afterwards, to optimize certain tasks, there created a module of data source to OpenSCADA DAQ.SMH2Gi with functions for direct SMH2Gi modules MC and MR acquisition, and also for variables exchange with process "logix", by the shared memory.

To build the original software environment the developer used previously discussed tools PTXDist of version 1.99.12. It was not necessary to build ToolChain, guessing the profile used to build the original software environment, because full building environment is available at the manufacturer's web site, packaged up as the Linux image for the VMWare virtual machine. The ready ToolChain profile was obtained from this image gcc-4.3.2-glibc-2.8-binutils-2.18-kernel-2.6.27-sanitized. Since it was not required to build the full RFS, it was decided to build OpenSCADA, using the ready ToolChain, separately. To build OpenSCADA the following libraries were previously built: "pcre-8.12" and "sqlite-3.7.6.2". Later, under building modules UI.WebCfgD and UI.WebVision task have built the libraries: "png-1.2.49", "jpeg-8a", "expat-2.0.1", "freetype-2.3.11", "fontconfig-2.6.0" and "gd-2.0.35". Then OpenSCADA was built in following way:
# Unpacking the toolkit $ cd /opt $ tar --lzma -xvf SMH2Gi-OSELAS.Toolchain.tlz # Initialization the build environment $ . /opt/OSELAS.Toolchain/enter_arm-v5te-linux-gnueabi.sh # Move to the source tree OpenSCADA, configuration and build $ cd /opt/OSELAS.Toolchain/OpenSCADA $ ./configure --host=arm-v5te-linux-gnueabi --prefix=/usr --sysconfdir=/etc CXXFLAGS="-O2 -D_REENTRANT" CFLAGS="-O2 -D_REENTRANT" --disable-MySQL --disable-FireBird --disable-PostgreSQL --disable-SoundCard --disable-SNMP --disable-QTStarter --disable-QTCfg --disable-Vision --enable-SMH2Gi $ make

As a result, the archive of OpenSCADA assembling was formed, which can be loaded to the panel PC SMH2Gi and unpacked there. The resulting OpenSCADA software environment is configured to start automatically when you start the controller through init-script "/etc/init.d/openscada". OpenSCADA assembling was successfully launched.

With regard to the software environment of the panel controller SMH2Gi in general it is necessary to make some remarks. The controller uses the Linux 2.6.29 kernel with the hard real-time extension that allows you to hold periodical intervals up to 100 microseconds. In addition, all critical system threads run with the real time planning management policy. In this case, although the processor does not have a math coprocessor, emulation is performed optimally in the form of SoftVFP. All this makes it possible for OpenSCADA to perform highly determinate control tasks at regular intervals up to 100 microseconds and with an acceptable computational performance.

5.6. AS-9260

Board AS-9260 is controller based on chip AT91RM9260, core ARM9(ARMv7), with peripheral devices set. The board targeted for development (maketing) projects based on microcontrollers with core ARM926EJ-S production by corporation Atmel, also that can be used for master controller of the target system.

To the board placed sockets USB2.0 (1 Host, 1 Device, Full-speed, 12Mb/s), DBGU, RS-232, RS-485, two 12-pins sockets for placing Ethernet 10/100 Mbps interface module, besides that have place for set two 80-pins sockets type PLD-80 for connect external modules with additional interfaces.

The boards AS-9260 peripheral with processor AT91sam9260 is minimal:

• sockets for interface USB type A and B;
• socket DRB-9 for interface DBGU (RS-232);
• socket PLS-3 for addition interface RS-232;
• socket PLD-20 for connect JTAG-emulator (ATSAM-ICE, AS-JTAG);
• chip ROM series DataFlash AT45DB642D-TU (case TSOP28);
• 2 chips SDRAM total capacity 32 or 64 MB;
• socket for external module Ethernet PHY connection.

Loader and kernel you can be found here http://www.at91.com/linux4sam. To U-boot let's set loading RootFS from USB-flash:
setenv bootargs root=/dev/sda1 rootdelay=9 rootfstype=ext2

The flash will format to FS EXT2 and to it will write RootFS Debian Lenny. Run the system and configure the internet connection nano /etc/network/interfaces:
auto lo iface lo inet loopback auto eth0 iface eth0 inet static address 192.168.ХХХ.ХХХ netmask 255.255.255.ХХХ gateway 192.168.ХХХ.ХХХ

Into /etc/inittab let's set autologin:
T0:23:respawn:/sbin/mingetty console vt100 --autologin root

Set repository for updating, into /etc/apt/sources.list
deb http://archive.debian.org/debian/ lenny main contrib

After upgrade let's download OpenSCADA sources and resolve dependencies. Natively compile SCADA fails by lack of memory. Some from the situation resolving solutions are next:

• Build image of RootFS:

• Start QEMU with RootFS image:

• Compile with next configuration:

• Write image with SCADA back to flash.
• Load and use.

The described method is far not the best then working to improve it. Similarly SCADA is installed to board AS-9200 with processor AT91RM9200.

5.7. Raspberry Pi, Pi2, Pi3; OrangePi Zero

"Raspberry Pi®" is a singleboard computer created for charity purposes. Designed to teach basic computer science in schools, positioned as a low-cost solution for novice developers. Developed by "Raspberry Pi Foundation". First board of Raspberry Pi was got to assembling and adaption of OpenSCADA from Maxim Lysenko. The board Raspberry Pi2 was purchased for tasks of OpenSCADA and adapting it to work with generic buses like I2c, SPI, 1Wire with different sensors on its. The board Raspberry Pi3 was purchased and sponsored by Proviron Holding NV for some debug and technical support.

The board has features:

Raspberry Pi
For working the board used special distributive Raspbian "Wheezy". Building OpenSCADA was done for LTS version 0.8.0.5 and Work version 0.8.1 direct on the board. For building had to expand swap memory size to 500 Mb due more memory need for some modules of OpenSCADA building by modern compiler (GCC 4.7) and with optimization (-O2). Result packages successfully installed and operation.

Graphical desktop environment into selected distributive built on LXDE 0.5.5, displayed in full resolution of the display through HDMI, or in resolution 640x480 through composite video-output. OpenSCADA successfully have started and have worked into graphical mode, but its performance insufficient for normal dynamic models of OpenSCADA execution.

Raspberry Pi 2 and 3

For working with the boards there also used a special distributive Raspbian "Wheezy". OpenSCADA has built for Work version 0.9 direct on the board and allowed memory here enough for this operation but it has 1MB and more, the building there allowed on all four threads. The building of OpenSCADA performs in packages which then placed into proper repository of Debian 7 from time to time of the buildings. Also for Raspbian "Jessie", mostly for the generic architecture ARMHF, there performs regular building of OpenSCADA by the OpenSCADA automatic builder into the cross-compiling environment and the result packages are placed into proper repository of Debian 8.

The typical graphical desktop environment into the selected distributive built on LXDE 0.5.5 (Wheezy) and 6 (Jessie) but it's replaced to TDE R14 for more features with low hardware demands. For remote access there was configured VNC access in display resolution 1024x768. OpenSCADA is successfully started and worked into graphical mode and the performance here enough already by the multi-threading.

For more free handling to the board was connected a WiFi adapter and on RPi3 it presents already.

To allow for operations with GPIO directly in OpenSCADA there was created a module DAQ.BCM2835 based on the library bcm2835. For now the module provides access to "Raspberry Pi" GPIO (0...31) as OpenSCADA DAQ's parameter attributes, static and dynamic functions, which the comparing information of performance shown here.

To the board there was connected a 16x2 text display 1602A and a program like to the original Python one was wrote into OpenSCADA by using the static functions of the module DAQ.BCM2835. As a result the program works fine and some faster to the Python original one.

To the board there were directly connected sensors DHT 11 and AM2303 (humidity and temperature) and a program like to the original Python program's C-language driver part was wrote into OpenSCADA by using the static functions of module DAQ.BCM2835.

To allow creation derivative DAQ templates with their configuration the dynamic linking to static external functions was added into DAQ.JavaLikeCakc?, like this:

To allow operation in OpenSCADA with devices on bus I2C the output transport "Serial" was adapted to the bus by selection the bus and a slave device's address (first byte of the sequence) set by IO control command I2C_SLAVE. In this way now to OpenSCADA there were connected:

• The 8-bit A/D and D/A converter chip PCF8591. Through the chip PCF8591 were connected sensors LM35 and LM335.
• The 8DIO converter chip PCF8574, which also adapted and tested for connection to 1602A.
• The barometric pressure/temperature/altitude Sensor BMP180.
• The memory chips AT24CXX by calls through the proper protocol.

The tracing task of the work out opened here.

Orange Pi Zero

For working with the board there used a special distributive Armbian "Jessie". As builds of OpenSCADA there have used the packages repository, mostly for the generic architecture ARMHF, for which performs regular building of OpenSCADA by the OpenSCADA automatic builder into the cross-compiling environment.

The board provides more low level buses (3xUART, 2xSPI, 2xI2C), despite its small size, and restricted GPIO in 16 pins which mostly used by the buses. The buses are standard but GPIO are some specific ones for which we need implement special support into the presented module DAQ.BCM2835 making it more unified one. Then there planed next tasks:

• connect a device to the I2C bus;
• connect a device to the Serial bus,
• try to adapt 1Wire (DS9097) to the Serial buses;
• the specific GPIO support implement for OpenSCADA;
• WiFi driver fix/update.

5.8. Asus Nexus 7 II

"Asus Nexus 7 II" — tablet computer of 2013 year edition with four-cores ARM-processor and sensor screen 7", released in conjunction of Asus and Google. Purchased for tasks of OpenSCADA and adapting it to work into the environment of OS Android and hardware of modern multicore CPU of ARM-architecture.

Image. OpenSCADA in Web and Qt5 for the native building.

Key specification of the tablet:

The tracing task of the work out opened here.

Assembling and starting OpenSCADA into the environment of OS Android

Installing of full-featured OS Linux and OpenSCADA starting
For different OS installing you need to unlock the loader and for original Android saving you need ensure multiboot.

The loader unlock and ROOT, from a Linux environment:

• Enable the debug mode of Android: "Configuration" -> "About the device", five times click into item "Building number".
• Set debug through USB: "Configuration" -> "Developers parameters", set proper property.
• Install the utility "adb" (Android Debug Bridge).
• Check for connection to the tablet: connect USB-cable to PC, call command "$ adb devices".
• Unlock the device:
  • Enable the tablet with connection to PC by the USB-cable and holding by buttons "Power" and "Sound lower" up to the bootloader screen appear.
  • Check for the boot-loader visibility: "$ fastboot devices".
  • Unlock: "$ fastboot oem unlock".
• Load and flash "TWRP recovery": load here, then flash it by command "$ fastboot flash recovery /Path-to-TWRP.img"
• Enter to the "Recovery" mode of the loader and provide access ROOT: select "Reboot" -> "Recovery" -> "ROOT", then "Reboot" -> "Sytem".
• Next, installation "SuperSU" for you will be proposed.

To provide the multiboot let install "MultiROM Manager" from "Play Market".