Traversing The Reference Marks; Possible Causes Of Errors - HEIDENHAIN iTNC 530 Service Manual

19.2 Traversing the Reference Marks

If no EnDat encoders are used, the reference marks need to be retraversed after every power
interruption.
After the reference marks have been traversed:

19.3 Possible Causes of Errors

The causes of error of encoders also apply here. --> See "Possible causes of errors" on page 18
– 279; See "Possible causes of errors" on page 18 – 279.
Especially for the referencing, the following causes of error are possible:
With old position encoders:
19 – 318
Note
Ask the machine operator about the referencing procedure at the machine concerned.
Respective information should also be included in the machine manual.
The software limit switches are activated.
The most recently saved datum and machine datum are reproduced.
PLC positioning and positioning with M91 and M92 become possible.
For axes in an open loop, the counter is set to the value in the machine parameter MP 960.x.
Defective trip dog
(the reference end position is not recognized)
Switch signal of the trip dog is too close to the reference pulse
(During reference run via the motor encoder --> The reference mark signal is recognized too
early or too late but not at the requested axis position.)
Magnet inside or outside scale housing shifted or defective
(wrong or no reference mark is evaluated)
Ref. mark selector plate shifted
(inside the scale housing, at the position of the ref. mark label outside the scale housing)
Removed or damaged enamel
(On some scales the ref. marks were deactivated with enamel; if it is removed by cleaning
with unsuitable cleaning agents and equipment, these marks are "reactivated".)
HEIDENHAIN Service Manual iTNC 530