ABB 800 drive -encoder error

[electrician1]

Hi,
I've got following problem -hope somebody can help- any input would be much appreciated

Machine runs with two motors powered by (ABB ACS800 drives) in master/slave configuration
On master drive we have intermittent encoder error (7301) which is popping up at motors low rpm and sometimes when speed is 0.
However the error is not popping up when drive is set to internal speed calculation
Parameter 33.01-Drive software version:AS7R7322
Parameter 33.02-Application sw version:ASARF012

Following has been done but it didn't resolf the problem:
1.Encoder is new one -replaced few months ago
2.Measured encoder waveform - ok
3.Checked cables,shields etc.. -ok
4.Checked all drive parameters-ok
5.Replaced RTAC pulse encoder interface module at the drive

 

[jraef]

Sounds like noise getting into the circuit.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[controlsdude]

Is the cabling coming into the enclosure unnecesaryly coiled? Is the power and encoder cable touching in any way? are the cables coiled together in the panel? Is the encoder cable ran in seperate conduit from the motor cable? Grounding is correctly done according to manufacturer?

 

[electrician1]

Grounds and shields are connected as per manuf. drawings. Cables coming into enclosures are not unnecessary coiled. Motors are close to 330ft far away from VFD drives and motor power cables are in separate cable tray.
Encoder cables are in cable tray together with 24V DC solenoid cables.
Measuring the encoder signal with scope meter we couldn’t observe any major noise etc.

 

[mikekilroy]

Is this a new application?
Or one that used to work fine and now does not?

If used to work, when did it stop working right? Think about anything that happened just before it stopped working right.... thunderstorm? power outage? rewired panel? etc?

If new app, then I agree it sounds like it is an installation issue with grounding/shielding.

Need to know above to be more helpful with ideas.........

 

[electrician1]

Its four years old application and just a month ago we started to deal with that problem.Application is still running without any problem but it’s quite annoying to have that alarm popping up all the time at our scada and drive screen.

 

[controlsdude]

I agree then with Mike that either some electrical storm or maybe look at incoming power or maybe your drive is failing. The error might be hinting at this possiblity.

 

[iop995]

If encoder and cables are ok, I think it's an error/problem in interface because error is signaled at low and zero speed only. Anyway check power supply line voltage at interface point and 50xx encoder parameters also.

 

[electrician1]

This has all been checked. We do have spare drive and we were actually thinking to install new drive just to see if it will generate the same problem

 

[Masbibe]

Check one by one channel of encoder by using only one channel for feedback (via parameters setting). Attach drawings of this part, encoder type and parameters file.

Milovan Milosevic