AC500-ECO Communication Modbus RTU With other Devices .
Here is the program which i wrote
and i wonder is there any (TX, RX) indicator in the plc eco or he vfd to know if the communication is ok or not , and if there is no indicator how could i know if the communication ok or not , for example in fatek rs584 card there is an rx,tx indicator and if the communication ok these indicator start flasher .
1. If I can see well, you are trying to read and write in the same start address (ADDR=0). That is not correct
Try first only with read block.
2. I'm not quite sure if your logic for block EN is working well - ensure that you have a regular pulses (requests) in both EN inputs.
The simplest method to try is EN:=not DONE and not ERR
3. For check if COM port is working, look for DONE, ERR, ERNO (done and err are true only for one cycle after request EN)
COM2 has no LED for Rx/Tx
To check if there're packets coming to ACS550 drive you may check out parameters in group 52 on drive's panel. They show number of messages received, sent, and various types of faulty ones.
If the drive receives messages and sends something back - then it might be something wrong with your program, if no messages are coming - problem could lay on physical level (cable, terminating resistors, polarisation etc.)