Since RSA, Inc. has been a distributor for Parker Automation for over 30 years, we have helped a lot of customers specify and deploy a lot of Parker components. Many times, this involves helping with mature components that get replaced with like items. As with many things in life, the devil is in the details; and the solution to a problem can be found in the most obvious of places.
For instance, we recently worked with a local food and beverage manufacture replace a Compax3 Positioning Drive/Controller and PA2 PowerStation HMI that had failed after many years of use on a Bartelt horizontal pouching machine. We transferred the program from the old HMI to the new and thought we were finished with the support. However, the following day the customer called back asking why the HMI could not change any of the parameters in the Compax3. So, the investigation began.
RSA Application Engineer: We verified the HMI program was working to the extent that we could, but without having the Compax3 we could not completely test it. What exactly is the HMI displaying?
Customer: All it is showing is that the status of the drive is ‘0.’
RSA Application Engineer: Can you tell me how you transferred the configuration file from the old Compax3 to the new?
Customer: I used the C3 Servo Manager and found the configuration on our server. Verified that I had the correct firmware version and then used the upload function. C3 Servo Manager told me that the download was successful, but no matter what I do, the HMI still tells me the status is ‘0.’
RSA Application Engineer: Great! That means we can eliminate the Compax3 as the issue. Let’s go back to the HMI. You have two drives connected to the PA2, correct?
Customer: Yes, I do. The other drive is working properly.
RSA Application Engineer: OK. Which COM port is the problem drive on?
Customer: COM2.
RSA Application Engineer: The ‘0’ status means that the drive is not communicating to the HMI and vice versa. COM2 can be configured as RS-232, RS-422 or RS-485. Can you look at the DIP switches located under the Compact Flash tray? There is a diagram on the side that will tell you how to configure the switches for the correct serial configuration.
Customer: That was it. Once I selected RS-232, the drive status changed and now I can change the parameters.
Those small DIP switches can be missed in a recommissioning. Once you set them you definitely forget about them, but they have a huge impact on the operation of the system. They also become “hidden” once you install the HMI in the panel door. Good thing we solved the problem quickly. I could use a good drink right now.