Circutor CVMk MODBUS communication protocol

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

Supported device types and versions


MODBUS RTU MASTER supports data reading from the analyzers Circutor CVMk.

Communication line configuration


  • Communication line category: Serial.
  • Parameters of asynchronous line depending on the design and type of device connection – see literature about Circutor.

Communication station configuration


  • Communication protocol: MODBUS Circutor CVMk.
  • Station address is a decimal number in the range of 0 up to 255 or a hexadecimal number with a hash at the beginning (e.g. #1A).


Station protocol parameters

There can be defined the following parameters:

Table 1

Key wordFull nameMeaningUnitDefault value
RCRetry CountNumber of retry calls when an error in communication occurs.-2
RTRetry TimeoutDelay between retry calls if an error in communication occurs.ms200 millisec.
WFTWait First TimeoutFirst waiting on the response after sending a call.ms100 millisec.
WTWait TimeoutDelay between the readings of a response until it is completed.ms100 millisec.
MWRMax Wait RetryNumber of retry response reading until it is completed.-15

String with protocol parameters is written according to this rule:

Key_word=value;Key_word=value;...

Example:

RC=1;RT=500;

If a key word with valid value has not been found in the initial string, default value is used according to Table 1.

I/O tag configuration


I/O tags: Ai

Address – decimal number in the range of 0 to 65535 – number of MODBUS double register, or a hexadecimal number with a hash at the beginning (e.g. #0ABC).

The values are read by 2 registers and interpreted as a 4 byte integer. The addresses of values are described in literature about Circutor.

Literature


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Changes and modifications


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Document revisions


  • Ver. 1.0 – May 9, 2000 – creation of document
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