Servotronix CDHD2S User Manual page 185

Application Setup
Any standard homing method (HOMETYPE) can be used.
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The HOMETYPE definition is for the Y1 (main) motor and is used on the entire gantry
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system. The HOMETYPE of Y2 (differential) must be set to HOMETYPE=35 (has no effect
on the axis).
Only the homing reference (index pulse, zero switch, limit switch) is considered for the Y1
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motor; the homing reference of the Y2 motor is ignored.
If the homing type relies on the limit switch to reverse direction during the home search
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process, the first limit switch detected on Y1 or Y2 will cause a change in direction.
If the homing type relies on the hard stop to change direction during the home search
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process, the first hard stop on either Y1 or Y2 will cause a change in direction.
Flexible gantry system homing
In a flexible CDHD2S gantry system, the homing requirements and methods are as follows:
Each of the two gantry motors must have an index switch or zero switch.
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Apply the same homing type to both Y-axes, and can be any of the following types:
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HOMETYPE1, 2 (limit switch and index pulse homing)
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HOMETYPE23, 24, 25, 26, 27, 28, 29 or 30 (limit switch and zero switch homing)
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HOMETYPE-33, -34 (index pulse homing after hard stop)
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HOMETYPE-56, -60 (zero switch homing after hard stop)
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When the homing command is issued to the gantry host, the following situations will occur:
1. The preliminary rough alignment is performed on both axes. The two are closely aligned
with each other but not perfectly aligned.
2. Both axes start moving simultaneously toward the limit switch or hard stop.
3. Both axes move in reverse direction at the same time and search for the Y1 axis homing
reference. The axis moves until it reaches the limit switch/hard stop in the opposite direction (on
the Y1 or Y2 axis).
4. The axes move in reverse direction at the same time, and search for the Y2 axis homing
reference.
5. Finally, to align the two axes orthogonally, the homing process moves the differential axis
based on the GANTRYOFFSET value. The gantry system returns to home.
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