OMV24 communication protocol

Supported device types and versions
Communication line configuration
Communication station configuration
I/O tag configuration
Redundant system
Errors and problems
Literature
Changes and modifications
Document revisions

Supported device types and versions

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Communication line configuration

• Communication line category: Serial, SerialOverUDP Device Redundant
• Parameters of the serial line according to the settings of telemetry transmission system.

Communication station configuration

• Communication protocol "OMV 24".
• Address parameter is not required. The communication line can be used only for one Gaspartner.

The text messages are not supported.

Station protocol parameters

Communication station - configuration dialog box - tab "Protocol parameters".
These parameters influence some optional parameters of the protocol. You can set the following station parameters:

Table 1

A string containing the protocol parameters is defined as follows:

Key_word=value;Key_word=value; ...

Example:

WT=400;PERIODE=20;

If there is used a keyword with an invalid value in the initialization string, there will be used corresponding default value according to Table 1.

I/O tag configuration

I/O tags: Ai, Ci, Di, Qi, Ao, Co, Do

The Gaspartners transfer each other data in blocks with defined periodicity. A received input block is analyzed and the values are assigned to the proper input tags according to the parameter Identifier (Ai, Ci, Di, or Qi). Output block consists of output tags (Ao, Co and Do). These output tags must contain a control object, tab "Control of output".
Note: I/O tag of Qi type, which is used as the control object, used for output tag Co.

Identifier

The blocks of data are transferred during this communication. Every object (I/O tag) has its unique number "Identifier", which is required. An identifier is a number in the range of 1 up to 998 (0 and 999 are reserved). The same values of Identifier can be used in both input and output blocks.

Exponent

Exponent is a value that should be defined for Ai, Ci, Ao, and Co tags. The input value from the communication is recalculated by a result 10^Exponent. The implicit value is 0 (i.e. input value *1). For Ao and Co tags, the calculation is the same and the result is sent by output data block. 

Decimal places

The number of decimal places for Ao (output tag). It defines an accuracy of sending data to Gaspartner.

Redundant system

This protocol supports two modes of activity:

1. Activity in the state of connection to the "hot" server (HS). The protocol executes an active communication, i.e. sends a request for data according to the configuration. 
2. Activity in the state of connection to the "stand-by" server (SBS). The protocol just reads and analyzes the received data. This state can be used for the whole communication line and all stations, which are defined on it, at any time with the help of parameter SCAN that should be used at least in one station.

A transition from SBS -> HS is executed with a transient phase, i.e. data are read for 1 minute to detect silence on the communication line, which means a detection whether the previous D2000 KOM, connected to the HS server, has switched to Mode 2.

Errors and problems

The error messages, mentioned below, may occur during the start or communication. It is recommended to activate the monitoring of communication in the configuration of line for easier identification of problem. You can choose it from these levels:

• Monitor (at least)
• Monitor & Disk (recommended)
• Disk (recommended)

When you set "Monitor & Disk" or "Disk", the file "line_name.LOG" occurs in the "Trace" subdirectory in the application directory on the computer with the running communication process. This file contains all the debug and error messages.

Literature

• TRANSGAS - RUHRGAS - OMV format specification document 1992-12-21.

Changes and modifications

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Document revisions

• Ver. 1.0 - September 18, 2003 - Creation of document