HEIDENHAIN ND 1300 OED and Crosshair Systems - Manual (Page 192)

174 QC-300 Series User’s Guide
Setting a new machine zero reference
A machine zero is established each time the QC-300 is powered. However, it might be necessary or con-
venient to change the location of the machine zero position to a new “home” position for measurements.
To set a new machine zero position:
Select the Machine Zero Offset data field, move the stage to the desired new machine zero position and
touch the Set button. The new machine zero for the current axis will be established and the offset displace-
ment from the original machine zero to the new machine zero will be shown in the Machine Zero Offset
data field. Repeat this pro-
cess for each axis.
CAUTION
SLEC and NLEC encoder error correction values are referred to a repeatable machine
zero location. If the machine zero location is set to a different XY position, SLEC and
NLEC correction values will no longer be valid.
Reversing the encoder count direction
Encoder count direction for each axis is toggled between normal and
reversed by repeatedly touching the Reversed choice field.
Enabling axis error messages
Encoder error messages for each axis can be displayed on the
LCD. These messages are enabled or disabled by repeatedly
touching the Enable Axis Errors choice field.
Specifying slew limit
The encoder data rate limit of the system is 500,000 counts per second. An encoder error message is
displayed when the encoder rate of travel exceeds the encoder velocity shown in the Slew Limit data field.
The Slew Limit velocity is calculated using the formula:
Slew Limit = (500,000 counts/second) X (encoder resolution distance/count)
For example, a 0.0005 mm/count encoder would have a Slew Limit of 25 mm/sec
Slew Limit = (500,000 counts/second) X (0.0005 mm/count) = 25 mm/sec
To change the velocity limit value, touch the Slew Limit data
field and enter a new velocity.