Need Help - Sinumerik 840D system

Dear All,

In oerlikon gear cutting machine, cutter spindle is A axis

Error 25000 A axis active encoder fault appears soon after switching on the system

We checked following :

a) Cable continuity from Motor upto 611 control card - found ok in Digital multimeter in Resistance Mode

Checked continuity between connector on junction box over Motor and cable plugged on encoder found OK

b) Interchanged control card from other axis (Siemens Part number is same for both the control cards)

c) Replaced Motor encoder with New one

d) Old NC archieve loaded to ensure nothing wrong with parameters but same alaram

Kindly advice what else could be the reason

Best Regards,

M. Rishikesh

Bad encoder on motor.

encoder or encoder cable because this fault start by hardware problem

dear sir
i thinks based on my experience you should check , the counting direction for A axis in NC machine parameter , in 840 D all axis mention by direction to use , you should check it before all .

have the active encoder checked, there may be an additional encoder on the axis and not using the motor encoder.

Could be a Heidenhain ROD type of encoder and yes, they do go wrong.

If no second encoder, motor encoder is faulty.

hello, did you found the solution?