Allen Bradley VFD problem

sns

Member
Join Date
Dec 2009
Location
Pakistan
Posts
42
We have six Allen Bradley PowerFlex 1336 PLUS II VFDs/Inverters installed at our plant connected through ControlNet using 1203-CN1 Scanport. The problem is that sometimes the fault light on the Scanport module starts blinking of fault and the HIM on the VFD display F 10 which is serial fault. The problem occurs randomly and has happened on all the six drives. The frequency of occurrence is also random. It came recently after a couple of months.
What could be the possible reasons for this? I’ve gone through the manual and none of the Actions the manual says are really applicable to my case.

Thanks
 
We have six Allen Bradley PowerFlex 1336 PLUS II VFDs/Inverters installed at our plant connected through ControlNet using 1203-CN1 Scanport. The problem is that sometimes the fault light on the Scanport module starts blinking of fault and the HIM on the VFD display F 10 which is serial fault. The problem occurs randomly and has happened on all the six drives. The frequency of occurrence is also random. It came recently after a couple of months.
What could be the possible reasons for this? I’ve gone through the manual and none of the Actions the manual says are really applicable to my case.

Thanks

We went through a similar problem with slightly different drives on control-net (1336 force). Our problem turned out that the scan port was not properly secured to the din rail. The ones we used grounded on the din-rail and if they weren't locked on the rail, they would cause a ton of noise on the network.

The funny thing was it would not cause the drive with the unsecured scan port to fault, another one on the network would fault. We had a meter that would measure noise on the network. When the scan port was locked down, no noise. If we would unsnap it and let it hang on the din rail, there would be a ton of noise and one of the drives on the network would randomly fault (every couple of hours).

I would also look for poor BNC connections.

Are you using AB connectors and taps?
 
I second checking the BNC connections idea. If not crimped with a proper tool the connections loosen over time and can cause havoc.
99.9% of ControlNet issues I’ve seen are traced back to the media. If all else fails buy some ends and a proper crimper and redo them all to spec. And use the proper taps....
 
jac speaks the truth.

If you don't find something obvious when checking over the BNC terminations, it might be worthwhile to get one of these

The installation at the plant that I worked at was terrible. We had the spec cable and used the proper connectors, but the contractor installed them with a knife and pliers (which we found out during commissioning our network). I quickly became a termination expert. I probably re-terminated 100 connections or more.

Like jac said, that took care of 99% of our problems. But the improperly grounded scan port was a nightmare. We replaced every piece of the drive that was serial faulting, one at a time and the problem never went away. I was cleaning out a drive down the chain and noticed that the scan-port was loose on the din-rail. Snapped it down and went about my business. I later realized that we had no more faults.

At first I thought dust collection in the MCC might have caused excess heat, which might have explained the faults. But later I brought out the tester, hooked it up, pulled the scan port off of the din-rail (out of curiosity) and sure enough, the noise went through the roof.

My situation is probably the least likely, but it is something easy to check while you are checking terminations.
 
VFD output lines are horribly noisy (electrically).

Make sure you are not running your serial cable in the same wireway/conduit as the motor leads.

Induction will do some crazy things to serial communications!
 
Thanks for the inputs.

The serial cable/control net cable is in the same tray as the power cables/motor leads.

Could that be causing it? I admit it was also my initial suspicion but this time the problem came after around three months and the drives are always running.
 
Another thing, can I disconnect the control net loop without disturbing the the other component in the loop (like profibus) or not?

Specifically, I want to check the terminations and grounding on each of the SCANport module so it'll require taking them out one at a time.

Thanks
 
We went through a similar problem with slightly different drives on control-net (1336 force). Our problem turned out that the scan port was not properly secured to the din rail. The ones we used grounded on the din-rail and if they weren't locked on the rail, they would cause a ton of noise on the network.

The funny thing was it would not cause the drive with the unsecured scan port to fault, another one on the network would fault. We had a meter that would measure noise on the network. When the scan port was locked down, no noise. If we would unsnap it and let it hang on the din rail, there would be a ton of noise and one of the drives on the network would randomly fault (every couple of hours).

I would also look for poor BNC connections.

Are you using AB connectors and taps?

@dmroeder

What meter were you using to measure this noise. I have very similar problem with some 1336 force and impact rives on scanport to RIO Adapters.

Fortunatly it only rears it's head every once in a while.
 
Can you mention the spec of the noise meter that you had? I think I am gonna need one here.

We went through a similar problem with slightly different drives on control-net (1336 force). Our problem turned out that the scan port was not properly secured to the din rail. The ones we used grounded on the din-rail and if they weren't locked on the rail, they would cause a ton of noise on the network.

The funny thing was it would not cause the drive with the unsecured scan port to fault, another one on the network would fault. We had a meter that would measure noise on the network. When the scan port was locked down, no noise. If we would unsnap it and let it hang on the din rail, there would be a ton of noise and one of the drives on the network would randomly fault (every couple of hours).

I would also look for poor BNC connections.

Are you using AB connectors and taps?
 
@dmroeder

What meter were you using to measure this noise. I have very similar problem with some 1336 force and impact rives on scanport to RIO Adapters.

Fortunatly it only rears it's head every once in a while.

Sorry Kid, I missed this post. See my previous post.
 

Similar Topics

Has anyone ever encountered an issue where PLC's seem to lose connectivity momentarily, as well as all ethernet VFD's in different areas across...
Replies
18
Views
3,916
Hi all, Client with a pretty much brand new AB Powerflex VFD starting throwing Fault 17: Input Phase Loss this afternoon. Started doing some...
Replies
6
Views
9,167
Hello all, Who have links for documentation,- how to connect Allen Bradley 3 phases VFD PF753 in test purposes using only 230V. Approximate...
Replies
3
Views
1,525
I want to connect the delta vfd to micrologix 1400 plc through modbus and want to read and write the data through compact logix L30 ER please help
Replies
2
Views
2,278
Hello everyone, I have a recent project that involves a Modicon M340 and a Allen Bradley Powerflex 753 VFD. I have only used a Modicon processor...
Replies
3
Views
4,689
Back
Top Bottom