Citect Lite

[rajsiyer 7]

Hi guys, Has anybody tried communicating Citect-Lite to a generic Modbus (on serial- RS-485) device ??, using Schneider's Aut-OFS?? If so, I'd like to know how it should be done. Thanks for looking in at least With best wishes, Raj S. Iyer

[Gambit 326]

Hello Raj, Should be easy enough. I always read holding register 1 first so 40001 to check communication then I add the other addresses. There is one thing you have to know about the modbus driver though. To check comms at start it will read a few digital inputs. However if you do not have these inputs you'll never get comms SO you'll have to change this parameter If your modbus device hasn't got these adresses: [MODBUSA]InitType The type of variable the MODBUSA protocol tries to read on startup, to allow communication to start. Allowable Values: 1 to 4. InitType Address Variable 1 00001 - 00017 Output status 2 10001 - 10017 Input status 3 40001 Output registers 4 30001 Input registers Default Value: 2 With this parameter, you can set different values for specific I/O devices or groups of I/O devices. See <A class=defaultStyleForNewLinks href="mk:@MSITStore:C:\KH\Citect\CitectScadav7.20\Bin\MODBUSA.chm::/modbus_devicegroup-specific_parameters.htm">Device/group-specific parameters. Edited 8 Feb 2011 by Gambit

[rajsiyer 7]

Hi Gambit, Thanks for your input. But the problem remains. Remember Citect lite uses only Schneider's Aut-OFS as the comm. driver. So the problem is to figure out how OFS can read data from any generic Modbus device. The modbus device we've got is a PID controller which DOES NOT come with its own OPC server. All the same, this communicates with Schneider's Modbus driver as is available in the Modicon Telemcanique's drivers manager version 2.5. It passes the "Modbus-Test" as well. Schneider's OPC server AUT.-OFS supports driver manager as described above.. so what I'm asking is how to really connect the two and use them in tandem with a 3rd party 'generic' modbus device. The comm-parameters you've suggested are valuable all the same. Thanks a million. Regards, & best wishes. Raj S. Iyer