ATV900 Encoder Module Error "INFJ" or "INF19" Diagnose


20 June 2022

"INFJ" or "INF19" means that there is an internal encoder error.
Diagnostic EMC issue.
Encoder card of ATV900 offer are much more sensible to EMC than option card of ATV71
It could be only on one device and this one will generate disturbance on all other drives.
1. Connect only one shielded wire between encoder and drive (avoid junction block), 
2. Make nice connection to ground on each side, motor side and drive side.
3. On drive side the shielded must be connected near the control. Check also ground connection of the motor itself and the drive itself
4. If possible check with an oscilloscope the quality of the encoder signals and of the encoder supply.
5. In case of long distance it is needed to sometime to add an external encoder supply. => could be nice to measure encoder consumption
6. Check cables path. Do not mix control signal and power signal
7. Check also if the mechanic to lock the option card is in good condition
8. In case of vibration, it is also possible for option card to moves a little bit and connection is lost
If we swap encoder card from one product to another
Check if the INFJ following the card or following the product. Then perhaps a problem on the option lock (or control block)
If possible and if following the card, check the ground connection
We have no dedicated actions in recent firmware about INF19, but it is always good to have latest firmware.