HEIDENHAIN ND 287 User Manual - Manual (Page 22)

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I Working with the ND 287 position display unit
I – 3 Basic functions of the
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Reference mark evaluation
The ND 287's REF reference mark evaluation feature automatically re-
establishes the relationship between axis-slide or length gauge
positions and display values that you last defined by setting the datum.
Reference mark evaluation if an incremental encoder is connected
(see Fig. I.12):
 If the REF symbol is flashing, cross over the reference marks.
 The REF mark evaluation feature determines the correct display
value and the REF symbol stops flashing.
Working without reference mark evaluation
 Press the NO REF soft key to exit the reference mark evaluation
routine and continue.

In order to activate the reference mark evaluation feature at a later
time, you can apply an external signal to pin 25 at connection X41
(see "Setting up the encoder" on page 71), or you can switch the
ND 287 off and then back on.
ND 287 shutdown
Switch off the ND 287. The measured values of a
series of measurements will not be retained on a
power cycle. The parameter settings, the error
compensation tables or measured values that have
been saved during statistical process control will stay
in memory.
Fig. I.12 Screen for establishing reference marks
Danger to workpiece!
If an encoder is set up without reference marks, or if the
reference marks have not been crossed over, then the
REF indicator will appear dimmed, and datums set from
any axis will be lost once power is turned off. This means
that it is not possible to re-establish the relationship
between axis slide positions and display values after a
power interruption (switch-off).