HEIDENHAIN PWM 20 - Manual (Page 56)

November 2014 Software description 57
Only after the reference mark has been traversed refer the absolute position values to this fixed
reference point.
As soon as the reference mark has been detected, the "Ref. mark" status display changes to
yellow.
The "Warnings" LED remains red and must be reset by hand.
Position display if an EIB 192 with Fanuc interface is connected.
Same procedure as with EnDat; here, the "Alarm" LED needs to be reset by hand.
Note
The reference mark must be traversed before the "Warnings" can be reset.