modbus communication

[gakpapa]

Hi guys,
happy new year
wis a better years for you

guys, i have two questions.
1. is there any of you ever use wireless radiolinx FHS for modbus 485 comunication?how to do that?
2. I have an MCM-3150. there are two serial port. I configured port 1 as a master, port two as a slave. Can i do a loop test on MCM-3150 by connecting those port via cross serial cable? i wanna check whether the master data will change or not if i change a data on the slave.

Thanks & regards
roe

 

[dchartier]

Hello gakpapa;
1.-Sorry, can't help you there, maybe someone else can answer on that question;
2.-We have done exactly that with an MVI56-MCM 2-port modbus card for Controllogix platform for testing purposes. So it should work the same on the SLC platform.
But just saying "you should use a cross-cable" has no meaning, either in RS-232 or RS-485. You will have to make sure the requirements for each port are correctly accounted for if you want to do a valid test.
Hope this helps,
Daniel Chartier