7/13/2024 12:07 PM | |
Joined: 4/14/2018 Last visit: 10/19/2024 Posts: 48 Rating: (1) |
We are trying to establish modbus rtu communication between s7 1200 plc and minilac MBAS 0600, Version-03. We need to read input coils from 10001, length 24 bits PLC - CPU 1212C (As master) Communication board: CB 1241 (RS485) We have Tried with Modbus_comm_load, and MB_COMM_LOAD, Since we are not getting the communication after a long try these are the findings, 1. Established communication in between client and PC with 'Mod poll' and monitored the data transfer, it was working fine as expected with the same data range and length. 2. Established communication in between 'Modbus slave' and PLC with same data range, 3. Monitored the communication between PLC and Device (Annunciator) with Dock-light, the data sequence monitored is exactly the same (When tested with PC to slave device, PLC to PC and device to PLC), these are the data monitored when using Modbus_comm_load and Mobus_master block 000320-Rx:01 02 00 00 00 18 78 00 000321-Tx:01 02 03 10 10 80 75 EB but when using MB_COMM block the data sequence is different, I have attached the Screen shot of the data sequence Even the Tx Rx LED is blinking in the Communication board, but the PLC is not reading the data, it shows error of 81EA, 80CA. Our assumption is that the slave device is getting the request from the PLC and replying with the proper format, and the PLC is getting the signals (since Rx is blinking) but somehow PLC blocks are not able to read the data, I have attached the manual of the device (Annunciator) If you guys have any suggestions or solutions to resolve the issue please reply, thanks in advance.
AttachmentData Sequence When MB_COMM and Manual.zip (364 Downloads) |
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7/20/2024 8:43 AM | |
Joined: 4/14/2018 Last visit: 10/19/2024 Posts: 48 Rating: (1) |
Thanks for your reply, 😊 I've attached the program. Current Status of the issue, ↘️↘️↘️ The client has tried with Schneider PLC(I don't know the exact model) but the communication is not establishing. But they have successfully established communication in between schneider HMI and the specified device, but still don't know why S71200 is not communicating. AttachmentModbus_with_MB_Comm_20240711_1701_20240720_1406.zip (251 Downloads) |
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