TNC145 homing problem

[locost_cam]

I have an interesting problem on Beaver mill with a TNC145 control. If you try to reference the Z axis it runs to the home switch, reverses and finds the index as it should. Once it finds the index it then runs away at full speed and trips out a gross positioning error. The same happens with the Y axis but not X.

I swapped Z and X encoders with no effect. I have also swapped the axis drive boards. Anyone seen this before?

[gus]

not enough info

back story please

has the machine ever run?

sounds like the parameters for counting direction are wrong

[locost_cam]

The machine was running fine then the Y axis ran away and tripped with a 'gross positioning error' halfway through a job. Now whenever you try to reference it runs away then faults immediately after referencing. I can't see it being a drive problem as it is perfectly controlled while referencing. Once it has faulted out, if you manually move the Z axis you can see the Z position display changing so the encoder appears to be working.

[machintek]

Bad velocity loop (tach)?

George

[locost_cam]

I'm not convinced. While homing the movement is smooth and stable. It is only once the index is found that it goes wild.

[gridley51]

Had it on the X axis on a V5 with Siemens axis drive.Can`t remember the cause now.What model have you got?

[locost_cam]

It is using Siemens drives but I am not sure what model. I can't get to the machine at the moment to check.