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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 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 protocol. You can set the following station parameters:

Table 1

Key word Full name Meaning Unit / size Default value
WT Wait Timeout Delay between the response reading until it is completed. ms 1000 millisec.
SCAN Scan-only Mode Permanent passive mode of data scan only (mode 2). YES/NO NO
PERIODE Write Periode Transmission period of output data block. A station must be in an active mode 1. If the valid data have not been received and three-time of this time elapses, the station switches to a communication error after. sec 60
TM_FACTOR Write Collision Delay Timeout of two functions:
  1. If there are some communication problems (full input block has not been received, noise ,etc.), the receipt is totally reinitiates and uncompleted data are ignored after the time elapses since receiving the last data.
  2. Output data block is sent after this time elapses since the receiving the last valid data.
sec 10
TRACE_VAL Trace Values Detailed tracing of data (e.g. through D2000 SysConsole). Detailed data about an analyzed value are written after every recorded line. YES/NO NO
TMASK Time Value Mask Mask for date and time conversion from received data. - yy-mm-dd hh:mi
MOXAT Moxa Timeout Timeout for detection of failure of one communication line on SerialOverUDP Device Redundant lines. After elapsing the timeout since receiving the last character, the communication is redirected to other communication line, i.e. reading/writing will be done via secondary / backup device. mi:ss 02:00
SENDT Send Delay Delay between sending individual lines of a communication message. sec 0.000

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 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 value are assigned to the proper input tag according to the parameter Identifier (Ai, Ci, Di or Qi). Output block consists of output tags (Ao, Co and Do). These output tags must contains 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. 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 block.

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

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 "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 "stand-by" server (SBS). The protocol just reads and analyzes the received data. This state can be used for 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 -> SS is executed with a transient phase, i.e. data are read during 1 minute to detect a silent on the communication line, which means a detection whether the previous D2000 KOM, connected to 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 subdirectory "\TRACE" in application directory on the computer with the running communication process. This file contains all the debug and error messages.

Error: >OMV24 - Id of Point: 'point_name1', Id: Identifier, is already used with Point: 'point_name2' !
Description: There cannot be two I/O tags with the same Identifier (address parameter) in input or output block.
Error: >OMV24 - Error in address, Point: 'point_name' !
Description: An error has occurred in the address parameters. Check all data on tab "Address" in I/O tag configuration dialog box.
Error: >OMV24 - Station: 'station_name', Received invalid character(s) !
Description: The forbidden characters were received through the communication. The protocol specification denies them. Only printable characters are permitted - '0' to '9' ,'A' to 'Z' and *;,.-: blank space, CR and LF.
Error: >OMV24 - Station: 'station_name', Data block error, invalid line number CountedLines / ReceivedLines !
Description: Number of lines (records) with CountedLines, which were analyzed from the data receive, is not in compliance with the number of lines ReceivedLines, which is referred on the last line with the value Identifier 999 (final record).
Error: OMV24 - Station: 'station_name', Unknown data block lines number !"
Description: Unable to read the final record Identifier 999 with total number of lines.
Error: >OMV24 - Station: 'station_name', Unknown data record quality (data line: 'data_record') !!
Description: The line with unknown character "Quality" has been received. The value is ignored.
Error:: >OMV24 - Station: 'station_name', Unconvertible value for value_type type (data line: 'data_record'), Point: 'point_name' !
Description: The received data record cannot be assigned to I/O tag point_name of type ValueType.  
Error: >OMV24 - Station: 'station_name', Unconvertible value for Qi type (data line: 'data_record'), Point: 'point_name' !
Description: The received value cannot be converted to Qi type. Transition values are 0-Error, 1-Off, 2-On, 3-Moving. The values out of range 0..3 cause that this error occurs.
Error: >OMV24 - Station: 'station_name', Unknown data record format (data line: 'data_record') !
Description: Received the unknown data format.
Error: >OMV24 - Station: 'station_name', Error during data analyzing (data line: 'data_record') !
Description: When analyzing the data record, unspecified error occurred (e.g. an attempt to change a text to number). The error can be caused when receiving the defective data. The protocol does not specify any check sum, therefore this situation can happen.

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
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