Altivar 12 control via Modbus


Thread Starter


I have two Altivar 12 drives on a 3 in 1 machine and am trying to send control words to start and stop the drives and change directions as well as send speed to the drives. I have used addresses of 8501 and 8602 and sent both hexadecimal and decimal words to these addresses. I used the table in the user manual to address the proper bits to start the drive and can not get the drive to respond in any way. I am using the Modbus test screen in Mach 3 and can read from the drive. I read known registers and was able to write to the above addresses and read the values back out that I wrote to the drive. I just can't get it to respond. I'm wondering if anyone has been able to write a command and or speed to one of these drives, and if so, how it was done.

Any help is appreciated.

All altivar drives must receive a run command in a certain way. On MODBUS tcp/ip you must write 3 different values in succession to start it. Can't remember on top of my head what the values are but they are explained in the MODBUS and MODBUS TCP/IP manuals.

Ill try to post a link.

Ps. If writing to the reference speed, do you see that that value at least changes in the drive? If not you must change you reference settings in the drive to point to the MODBUS link.