Problem with MODBUS RTU between AC800M and AC500
I'm having a problem with a MODBUS RTU between AC800M acting as MASTER and AC500 acting as SLAVE.
The AC500 is working correctly and i tested it through a simulator named CALTA ( that was the MASTER ).
I'm using COM3 for AC800M and an handmade cable that i made following the original one ( TK853).
The Status is giving an error 4929 = Timeout, slave not responding.
I'm trying to read From AC500 (register 40001) a value = 20.
I give you a picture of the cable connections and a screen of the AC800M logic.
It have to work perfectly. Please provide more detail information for your slave:
What type of AC500 and COM port do you have? Is it RS485 or RS232?
Try with setting AC500's slave address different than 1, for example 5.
Note that COM3 of AC800M is RS232 only! May be you will need RS232/RS485 converter.
The diagram of COM3 / AC800 is the following
You have to use pins 3, 5, 6 from AC800M side.
Always set poll time = 0 in AC800M
What do you mean register 40001 in AC500 - it should be something like %MW0.1 ???
The start address in AC800 in that case should be %MW10#1