powerflex 70, PF70 communications

[LabTech1101]

I know there are already at least two similar questions about this in the past, but the newest one I found is from 2007. Does anyone have experience communicating between (CRio and/or LabView) and an Allen Bradley PowerFlex 70 variable frequency drive? I have a system that I would like to upgrade and called in with this question. They gave me a service #2082431 (for you forum monitors) and then emailed me that I should check the forums for an answer. I had already checked the forums and driver list before calling, but apparently they thought it would be faster for me to type all this in instead of just transferring me to whoever monitors these forums.

So here is my situation:

I have a system that has Allen Bradley PLC, VFD, and RSView. We had a power failure which caused single-phasing and burnt up the VFD. I need to buy another variable frequency drive to replace the original. The original drive is obsolete. A replacement that has been quoted is the PF70, part # 20AD034A0AYNANC0. I don't know if that is a real part number or a vendor specific number. Anyway, my short-term plan is to buy this drive and use it in the SLC500 and RSView control system that is already there. This will get the machine going again. However, in the future I would like to start using NI products instead of the AB PLC and RSView. NI does not sell frequency drives so I have to ask if, in the future, the Allen Bradley PowerFlex 70 variable frequency drive will be able to communicate with anything I can purchase from NI. I expect to try to use a CRio controller and LabView2013 to re-control the machine. I do not have any experience with serial or ethernet communications between anything that is not plug and play so I am just trying to find out:

1. Can LabView2013 or CompactRio talk to an Allen Bradly PowerFlex 70 VFD?

2. How hard is it to do in terms of controlling the drive in real time and pulling data from it to use for control and data collection?

Thanks.

[Prickly_Pear]

This is a great question. At National Instruments, we provide motion controllers for servo and stepper motor drives. These controllers output DC and TTL signals to their drives, respectively. Our motion controllers accept feedback signals from the motor's encoder in order to provide precision. They also have PID algorithms built in as well trajectory mapping.

Variable frequency drives are less common. They accept two or three sinusoidal signals as input. The amplitude and velocity of these signals controls the torque and speed of the motor. We do not sell variable frequency motor controllers. 

I believe that you have two options for controlling this motor:

1. You could use a multifunction DAQ board to output the sinusoidal signals. You would then need write your own motion controller in LabVIEW for the VF motor system. This would be difficult considering that it would need to include programming for accelerating, braking, halt, etc. It would need to accept encoder feedback and calculate trajectories. I highly recommend that you avoid having to do this.

2. The Powerflex 70 appears to have an ethernet port as an optional accessory. It is possible that this is a "smart drive" if it has its own microcontroller onboard. If so, you might be able to send TTL communication message to the drive and it would be able to follow your commands. I believe that this is the best method to pursue. It would be a good idea to contact Allen-Bradley to confirm that this is possible. If so, make sure to ask what TTL messages will perform each action that you want.

Take care and good luck on your project,

Jeremy P.