Atmospheric Pre-aligner Manual
4000-0015 Rev 1
43
Home Test and Set
Each pre-aligner motor is factory set such that the distance between the
Home switch and the Encoder index is always between 1/3 and 2/3 of a
motor revolution away. This is critical for maintaining repeatability of the
Home position of each axis at a given mechanical calibration.
This diagnostic step measures and displays the Distance to Index of the r
and z axes. Note that the t axis does not have a Home Switch.
The homing procedure moves an axis to its Home switch and then moves
in the opposite direction to find the encoder index. (The encoder index is
one encoder revolution mark).
H----------------------------
^
--------...
Home Sw Index
1) <<--------------------... (First move)
2) ----------------------------> (Second move)
│<--------------------->│
Distance to Index
If the Distance to Index is too short, the controller can miss the first
occurrence of index signal because it occurs too soon after the Home
switch signal. Thus, the motor is required to move one more revolution to
generate the signal. At a particular distance, this doesn’t happen every
time and thus creates two different home positions, where the second
home is too far.
This test determines the Distance to Index, evaluates it, and assists in
making the correction. Use these instructions only if you have replaced a
pulley, belt or motor, or if the belt slips.
1. Press Enter. The Amplifier board initializes. If there is no closed
loop, the test stops. If this happens, check the connection.
2. You are prompted to select an axis to home. Use the toggle buttons to
select the axis.
3. The axis homes, stopping at the home switch and then at the index
mark. The Distance to Index is displayed in encoder counts.
(One revolution is four times the encoder pulses per channel.)
T:
R: XXXXXXX
Z:
Distance to Index
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