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 Circutor CVMk analyzers.

Communication line configuration


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

Communication station configuration


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


Station protocol parameters

There can be defined the following parameters:

Table 1

KeywordFull nameMeaningUnitDefault value
RC
Retry CountThe number of request retries when an error in communication occurs.-2
RT
Retry TimeoutDelay between request retries if an error in communication occurs.ms200 millisec.
WFT
Wait First TimeoutFirst waiting for the response after sending a request.ms100 millisec.
WT
Wait TimeoutDelay between the readings of a response until it is completed.ms100 millisec.
MWR
Max Wait RetryThe number of response reading retries until the response 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 keyword with a valid value has not been found in the initial string, the default value is used according to Table 1.

I/O tag configuration


I/O tags: Ai

Address – a number in the range of 0 to 65535 – number of MODBUS double register. It can be specified as a decimal number 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 the literature about Circutor.

Literature


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Changes and modifications


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Document revisions


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

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