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The module <SelfSystem> of the subsystem "Protocols"

Module: SelfSystem
Name: OpenSCADA system own protocol
Type: Protocol
Version: 1.2
Author: Roman Savochenko, Maxim Lysenko (2012)
Description: Provides own OpenSCADA protocol based at XML and one's control interface.
License: GPL



The module of the transport protocol SelfSystem is designed to reflect the interface management of OpenSCADA system to the network, to provide an opportunity to the external systems to interact with the OpenSCADA system, as well as for the interaction of the stations constructed on the basis of OpenSCADA among themselves.

The first experience of using the functions of this module was the support of remote configuration of one OpenSCADA station from another through the network, by means of the module of configuration QTCfg.

1. The syntax of the protocol

The protocol is built on the mechanism of request-response. Requests and their structure are summarized in Table 1.

Table 1 Structure of the request.

REQ: "SES_OPEN {user} {password}\n"
REZ OK: "REZ 0 {ses_id}\n"
REZ ERR: "REZ 1 Auth error. User or password error.\n"
The request for the opening of the session on behalf of the user user with the password password. In case of success it will be received the session identifier, otherwise the code and the error message.
REQ: "SES_CLOSE {ses_id}\n"
REZ: "REZ 0\n"
Closure of the session. The result is always successful.
REQ 1: "REQ {ses_id} {req_size}\n{control interface command}"
REQ 2: "REQDIR {user} {password} {req_size}\n{control interface command}"
REZ OK: "REZ 0 {rez_size}\n{control interface command result}"
REZ ERR: "REZ 1 Auth error. Session is not valid.\n"
REZ ERR: "REZ 2 {control interface err}"
The main requests: the session and the direct are implemented by sending the standard command of OpenSCADA control interface to the field control interface command. As the result will it be received an answer from the management interface control interface command result or one of the errors.
REZ ERR: "REZ 3 Command format error.\n"
Any invalid request.

Protocol supports the package of traffic. Only the data of the management interface is to be packed control interface command and control interface command result. The fact of the arrival of packaged request or response is determined by the negative value of the size of the request req_size or response rez_size.

To control the parameters of the package the module provides the configuration form (Fig. 1).

The form of the configuration of the module parameters. (86 )
Fig.1. The form of the configuration of the module parameters.

On this form, you can:

2.The internal structure of an outgoing protocol

The internal structure if formed by means of the tree of XML requests of the language OpenSCADA control interface with the reservation of the redundant additional service attributes of the protocol in the root tag:

rqDir sign of the sending the message passing the procedure of the opening the session (0-open session, 1-send immediately);
rqUser user;
rqPass password;
rqAuthForce force authentication update;
conTm force connection timeout.

The result of the request is the tree of XML language of the management interface of OpenSCADA.


Referring pages: HomePageEn/Doc

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