Controller Failures, Power Quality Problems?

[zmanvortex]

Hi all, we are an oem manufacturer of a stair routing machine. We have quite a few of the machines running fine except one that we installed about a year ago. It uses a PC based controller and a motion control card. There are some very weird things going on with this machine that we have never experienced with any of our other machines. It had been writing corrupted data to a motion file and the video had some funky colors. We replaced the pc, hard drive, and motion card. It ran fine for a few hours and then started acting up again. Communications between the motion card and the pc fails and never recovers until a reboot and now it has started writing corrupted data to the hard drive again. We have replaced all of the components and software so now we are considering looking at the incoming power. Has any one had any experiences similar to ours and what is the proper procedure to get a utility to monitor power, or record transients and surges ourself. I know the question is a little off the plc subject but it is a controller and you guys have helped me so much in the past. Thanks again.

 

[liebsce]

I experienced some of the same problems you described with a PC based Robot Control System a while back. It was solved by placing a SOLA
UPS to filter and condition the incomming power.

 

[Pierre]

It was solved by placing a SOLA UPS to filter and condition the incomming power.

This would defenitly be my first option.

 

[zmanvortex]

We have an APC Back-UPS 300 in place and I am in the process of finding out exactly what kind of protection it provides. So far I know that it is an Uninterupted Power Supply and surge protector, but will it filter out any kind of harmful power to the controller? We are at a loss as to what may be causing the hardware to fail. Thanks Again.

 

[ArikBY]

Try to put RF filter on the power line of your motion controler.
check if all the cable screened.
Check also your ground.
BTW who made the motion controler I had lot of problem like that with ACS.

 

[zmanvortex]

The motion controller is an ISA card inserted into the PC backplane so it runs on the same power the PC is running on. It is an Acroloop 2000 motion controller , but the communications with the motion controller is not the only thing failing. We are getting corrupted files (I assume when we write the files the RAM has been corrupted by something) and also the previous pc had video problems. None of our other machines have experienced problems even close to this one. I contacted the company who makes our UPS's and they told me that during an undervoltage condition ( < 106 Volts ) the UPS puts out a square wave until incoming power is restored, they also informed me that the UPS will not filter out RF or transients. We are still scratching our heads on this one. I am going to have the customer see if he can get his power utility to perform a test on the incoming power for quality. I will just have to keep chipping away and ruling things out, meanwhile any more help would be appreciated. Thanks.

 

[Jiri Toman]

What kind of power are you using? Is it a 120 VAC derived from a lighting transformer or do you have an isolation transformer that
steps down from 480 VAC?
If you are using a plant lighting transformer then power dips are a real possibility. The transformer might be used to power all sorts of other loads.

Isolation transformer 480/120 VAC would be a better choice.

Motion and servo controllers can suffer from another problem in a high resistance ground system. If you are experiencing a
ground fault somewhere within the plant, the controller might fault out. I have had this experience with Arburg molding machines.
The dosage (screw) motor is a servo that would fault each time there was a ground fault somewhere in the plant.
In order to get around this problem I had to isolate the servo controller with an isolation transformer 480 VAC primary / 480 VAC
secondary wye (star) configuration with the neutral grounded.

 

[zmanvortex]

We are tapping 2 legs of 240V 3PH on a transformer on our machine to get 120VAC. We need the 240 3PH to run the router motors. The UPS we are using does not have any line conditioners so I am a little suspicious of this being a problem. The next step we are going to take is to have his power company inspect the incoming power at the machine. One question, should the step down transformer on the machine filter out some of the dirty power?

 

[ArikBY]

Check if you have "harmonic" problem.sometimes it cause weird things,