I am developing a simple training demo for Motion Control. The system consists of an S7 1511 PLC, CU320 double motor controller, 2 small Siemens servo motors with encoders and a TP700 HMI.

All of the code compiles, both hardware and software, and downloads successfully. CPU and CU320 start and run fine, all green lights. Going online, I get no errors or indications of any problems. Both drives commission fine. All good so far.

My problem comes in when trying to get the TO_PosiitioningAxis V6.0, that is used in my demo, to execute properly.

The bit "#AxisTO.StatusDrive.CommunicationOK" is low, preventing the TO from operating. See attachment. This code is from the call to my Axis Control instance FB that used my TO Object.

Since I can't see inside of the TO, I can't tell why there is a problem. I've check the communications configuration for both the drive and the PLC and all seems well. I've checked the diagnostics buffers and everything seems to be operating properly.

I've gotten to the point that I can't tell what is wrong so that I can make the needed correction.

Any help is muchly appreciated.

Thanks