Kister Packer Sercos Problems - Electrician Talk - Professional Electrical Contractors Forum

ABB Drone · 10-27-2009, 02:51 AM

Hi All,
I am having trouble with a Packaging machine Servo system and am not sure of where the problem would be. It is using a Rexroth ECODRIVE system and comms to a Logix 5000 processor. The error that is coming up on the drive is F253 and the PPC says sercos disconnected. I cycle the power to the unit and the fault resets and away it goes, could be for a long time ,ie a day ,but usually it happens about 10 to 15 times over an 8 hour run. If anyone knows about these systems and can point me in the right direction that would be highly appreciated.

p_logix · 10-27-2009, 08:07 PM

Quote:

Originally Posted by ABB Drone

Hi All,
I am having trouble with a Packaging machine Servo system and am not sure of where the problem would be. It is using a Rexroth ECODRIVE system and comms to a Logix 5000 processor. The error that is coming up on the drive is F253 and the PPC says sercos disconnected. I cycle the power to the unit and the fault resets and away it goes, could be for a long time ,ie a day ,but usually it happens about 10 to 15 times over an 8 hour run. If anyone knows about these systems and can point me in the right direction that would be highly appreciated.

At my job we have a Kisters packer with a Controllogix PLC , and Allen Bradley servo drives for motion. The sercos interface should just be a single card controlling the comms between all the servo drives on the loop. Anytime one of you're drives are faulted on any axis your sercos loop will not be closed. Investigate why the drive is faulting.

This came right from the manual....
F253 Incr. encoder emulator: pulse frequency too high

Cause:

The incremental encoder emulator can process a maximum of 2047
increments per sample period 500μs ); this value has been exceeded.
Remedial action:

1. Reduce the

number of lines of the incremental encoder emulator

(P-0-0502).

or
2. Reduce the travel

velocity.
See function description: "Activating Encoder Emulation".

I have never worked on a rexroth drive before but it should be similar to a ultra 3000 or a Kinetix 6000 Allen Bradley drive.

Its all pointing to the encoder which resides in the servo motor. It can be a parameter was changed in the PLC. We have all our programs saved to our server so if I ever suspect a parameter may have changed I just dump the program back to the controller. It could also be that the servo motor does not match the part number in the PLC configuration for that axis. So the encoder pulse per revolution does not match up with the drive and motor.

Anyone of these parameters should be adjustable from the RS5000 software. Just look in your motion parameters properties tab. The encoder should be built in the motor and you should be able to test the motor feedback by running a few test in the controllogix RS5000 software. Under the module properties for that particular axis.

I would investigate all the parameters first then look into what could have possibly changed. Did they speed up the packer ? Hows the connection on the servo motor feedback cable? Is there a mechanical problem/ loose coupling? Can you swap out the servo to another axis and see if the problem moves to another drive?

Let us know what you find.

ABB Drone · 10-28-2009, 12:57 AM

Thanks for the heads up, I have allready checked most of these ideas that you have suggested, but I have not looked at the software to check the motion parameters properties tab. This is a good way to head. as for changing out the servo to a new axis to see if the problem moves with the drive. Unless I can do it in the software it will not be possible as this is the main drive and is bigger than all the other drives. And the company I work for doesn't have spares so I can't change anything to eliminate the problem. Thankyou for your help ,it has been good to get some fresh ideas. I will let you know what it turns out to be.