timmyh

Has anyone worked with this program before. I put it in and it worked ok. I kept on getting crc errors and faulting out the processor. I put in a patch to fix the fault and I thought I did some coding to make it work, but I kept on getting timeouts. Taking a closer look at the SlaveRecMonitor routine I noticed that before they read the serial port they check how many chars. are on the serial port, do some checking and then read the serial port chars again. why would they do this. I put an afi comment on the rung and it works perfect now. Is it possible that I could be getting bad data? The program is in the project folder in your rslogix 5000 folder(its only in v13 and up) if you want to look at it. Anybody has any clues let me know. I will also attach it. Thanks Tim ModbusSlave.ACD

We did not want to put in a new opc server. If you look in the logix projects folder there are sample programs to get logix to communicate over modbus via serial port. I get most of the program. Execpt how the data is stored and transfered. And this affects how lay out my tag structure in logix.

Hi, I am trying to get Compact logix communicating over a mb1 driver. Right now I am just trying to wrap my head around the sample program for modbus slave. I dont have the controller yet so I can not do any testing. My big question now is how is the data stored in logix. If I have tag with the address 40001 does that refer to Mod_DataHoldReg4[1]. I know it would be easier to use the prosoft card but my boss thinks it might be worth while to try and use this program. So if anyone has used this before please let me know. Your help would be greatly appreciated Thanks