Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Tue, 22 May 2012 19:59:01 +0000

Folks,

Release R2-4 of the EPICS "modbus" module is now available. This is from the release notes:

•Improved support for different Modbus data types. 
  ◦Added support for 7 new Modbus data types: 
    ■16-bit signed integer
    ■32-bit integer, little-endian
    ■32-bit integer, big-endian
    ■32-bit float, little-endian
    ■32-bit float, big-endian
    ■64-bit float, little-endian
    ■64-bit float, big-endian

  ◦Added support to allow the Modbus data type to be specified on a per-record bas using the asyn drvUser field. Previously all records connected to a Modbus asyn port driver had the same Modbus data type, because each Modbus port driver was limited to a single data type.

  ◦If the drvUser string in the link specification is omitted, or if it is the default of MODBUS_DATA then the record will use the modbusDataType defined in drvModbusAsynConfigure. This is backwards compatible, and existing IOCs will continue to work with no changes to databases or startup scripts.

  ◦Added new example IOC script, substitutions file, and medm screens to test all data types. The testing was done with a Modbus slave simulator.

•Added special treatment for Wago devices. These device are different from other Modbus devices because the address to read back a register is not the same as the address to write the register. The readback address is the write address plus 0x200. This means that in previous versions of this driver the initial readback value for Modbus write operations to Wago devices was incorrect. This was fixed by adding the 0x200 offset to the readback address if the plcType argument to drvModbusAsynConfigure contains the substring "Wago" (case sensitive).

•Added support for passing status information back to device support in callbacks for I/O Intr scanned records. Support for this was added in asyn R4-19. This means that if the Modbus device communications returns errors that I/O Intr scanned records will now have their alarm status set correctly.

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 tar file is here:
http://cars.uchicago.edu/software/pub/modbusR2-4.tgz

Cheers,
Mark

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System