Experimental Physics and
Industrial Control System

Folks,

 

Just after releasing R2-10 this morning I realized there was an important outstanding pull request.  I have merged it and done some testing, so I am now releasing 2-10-1.

 

This is the new item from the release notes:

 

- Previously the Modbus/TCP transaction ID was set to 1 on writes and ignored on reads.

  Now the Modbus transaction ID is incremented by 1 on each message sent by the driver.

  On the reply the driver waits until a message with the correct transaction ID is received, ignoring messages with any other transaction ID.

  This is more robust, especially for Modbus/UDP links. Thanks to Eric Norum for this.

 

This change assumes that the Modbus server correctly implements the Modbus/TCP specification which requires it to echo back the transaction ID that it receives.  I have tested this on several Modbus servers.  If in the future we find that there are non-compliant Modbus servers then we can add an option to disable the check on the received messages.

 

 

The home page is here:

http://cars.uchicago.edu/software/epics/modbus.html

 

The release notes are here:

http://cars.uchicago.edu/software/epics/modbusReleaseNotes.html

 

The documentation is here:

http://cars.uchicago.edu/software/epics/modbusDoc.html

 

The repository is on Github:

https://github.com/epics-modules/modbus

,

Mark