OMV24
OMV24 communication protocol
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
Keyword | 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 | A permanent passive mode of data scan only (mode 2). | YES/NO | NO |
PERIODE | Write Periode | Transmission period of the 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 | A timeout of two functions:
| sec | 10 |
TRACE_VAL | Trace Values | Detailed tracking of data (e.g. through D2000 SysConsole). Detailed data about an analyzed value is written after every received line (record). | 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 another communication line, i.e. reading/writing will be done via a secondary/backup device. | mi:ss | 02:00 |
SENDT | Send Delay | The delay between sending individual lines of a communication message. | sec | 0.000 |
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:
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.
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.