HELP! Problem with C axis referencing on ITNC530

Dear Forum members
I need you're assistance with one weird problem

I have omv Parapas group cnc machine with heidenhain itnc530 . And there's an certain problem which we face on a daily basis and trying to find out why. When we start and initialize the cnc and the controller ,At first we have to do Reference to all axes and we ref all axes . When we get last axis (swivel head axis c)We facing some strange behavior which we don't understand why it happening.

• When it start its reference move – it should always go in one direction until it gets to its reference mark and the axis stops.

In my machine the axis doesn't go in one direction to its reference mark , sometimes it goes to the positive direction and sometimes to negative direction and get stuck in overtravel position.And if it gets to the Overtravel emg position and turn emg signal on and then it require to do certain procedure(not with handle or jog or manual operation due to the emg state) to return the axis to its normal operating range.

We suffers from this for 3 years which happens few times a day.

Is it possible it is software related problem? Because in the past we replaced the axis encoder (rotary type) and it kept happening , also aligning of the OT sensors and nothing.

Or maybe you suspect it can be something else
please let me know what do you think of this

your new encoder should be checked first
if its ok, then Encoder cable to be checked.

Or Any of Limit switches getting triggered during C-axis rotation
your case is interesting......
please check and reply

Regards
Senthil kumar

Hi UGS,

Have you solved your problem? If not, please look for a proximity sensor on the axis. In my machines, I have a proximity which tells the machine whether it had to reference forward or backwards based on where the axis is at the time of switch on. If the proximity is ON, that means the axis is ahead of the reference marker and would hit the dead stop before it references, it would go in the direction opposite what it would usually. This is the normal logic for machines with rotary axes wherein the travel is not infinite.

There are two possible failure points-
1. Proximity might be in bad condition or physically contaminated causing wrong signal feedback
2. .There might be an electrical short circuit or noise in the system causing wrong feedback
3. The proximity mount may have become loose and shaking around

Best of luck with the diagnosis!

Best regards
Jaideep