When I downloaded my program on site, I successfully communicated with the first machine, however with the two other machines I got the error 80A1 and modbus status "TRCV".
I tested my program with ModRSSim and successfully communicated to the plc on simulation by using 3 laptops as the modbus server. However, on actual machines only one machine is communicating correctly and I got the error I mentioned above.
Is it correct to assume that I can only call Function code 3 alternately between the 3 machines one at a time before I trigger another request? Or is it okay to trigger the request to read the holding registers simultaneously?
Thanks and I hope someone can give me an idea on this problem.