SEW EURODRIVE Drive Inverter Fault F14

[Gabriel Ferreira]

I'm having a SEW Drive Inverter fault 14 which is a Encoder fault. The subcode that I have on movitools is the 27 Encoder error - encoder connection or encocer is defective.
On the manual the possible cause is: Encoder cable or shield not connected correctly. Short circuit/broken encoder wire or Encoder defective.
The solution is: check encoder cable and shield for correct connection, short circuit and broken wire, but I already changed:

Motor encoder and it's cable;
Absolute encoder and it's cable;
I installed a new SEW Drive Inverter and a new encoder board DEH11B

All the pieces that I removed from the defective machine are working on the other machines. The fault happens intermitently and I have to switch off the machine like it's necessary to "cool down" the system and then the motor and drive works for a few hours until I have the fault again 

The inverter model is: Movidrive MDX61B0370-503-4-00
The motor model is: DRE180M4

Could some one help me with that? Does some one already had this isse?
The only think that i didn't change is the motor, but I would like to have sure that it's not something usual that I missed instead of removing a 300kg servo motor.

[Red Dog]

I had an issue very much like this- I chased my tail for some time, changing encoder card, drives and checking terminals on the encoder. in my case it ended up to be- when the encoder cable was installed it came into a terminal strip- and then from the terminal strip to the drive. I had a loose connection on the terminal strip.

Might be worth a look.

[Gabriel Ferreira]

Tks Red Dog, I'll check it 

[Gabriel Ferreira]

There is no connection box.

The wire goes is connected in the motor encoder and goes straight to the drive inverter

[kaiser_will]

New motor encoder, new motor encoder cable, new motor drive, new drive encoder board.  So hardware-wise, the main components are new. 

Have you verified the encoder cable is properly specified?

Does this encoder have an absolute battery backup that is drained or not functioning?

Does the fault occur immediately, or after some time of operation?

Had this fault condition been happening for some time or is it a new event?

How far away is the encoder from the motor drive and  how is the encoder cable routed?  You could have the encoder cable routed next to a load with a large EMF.

Do you have access to a power analyzer?  If so, it would be worthwhile to monitor...power at the motor, encoder shield at the motor, encoder shield at the drive.  I have seen poor ground bonding practices wreak havoc on encoder feedback signals.

[Gabriel Ferreira]

Have you verified the encoder cable is properly specified? Yes, I got it from SEW

Does this encoder have an absolute battery backup that is drained or not functioning?  No battery in this encoder.

Does the fault occur immediately, or after some time of operation? After some time of operation and when the error comes the machine can't move. I need to switch off for a while and then it starts working again.

Had this fault condition been happening for some time or is it a new event? This fault started 1 month ago but it was sporadically and I could reset with no trouble, but now it's worse machine can't move

How far away is the encoder from the motor drive and  how is the encoder cable routed? cable has less than 10 meters (32 feet) and it goes inside of a metallic cable tray gets inside of the cabinet. The place where the encoder cabe is grounded are in the proper motor and in the drive inverter.

Do you have access to a power analyzer?  Yes I have and I'll get this results soon. But I got your point. I'll reinforce the ground of the encoder cable shield and also check the ground of thid drive inverter and the machine itself.

I'll return with some feedback since I have more news. Thanks for the support for far. 

[kaiser_will]

Factory SEW components; not a new problem; problem occurrence is more frequent (i.e., dynamic not static), many factory components changed out => it appears the problem is degrading and not fixed.

I chased a similar problem with a NON-SEW drive for a long time to find the root-cause...someone installed a sump pump and pulled power from the same circuit that feeds the motor drive (sump ON was injecting enough noise to mess with the VFD encoder feedback).  Fixing this lead to analyzing all ground bonding to find many, many other problems that had not turned up on anyone's list.