CN0170 HARDWARE MANUAL
In execution of the homing instruction, the motor seeks out the closed to
open transition of the Home input switch. This permits the Home position
to be located anywhere in the travel range of the motor if a cam operated
Home input switch is used.
If the Home position is located at one extreme of the permissible travel
range, or the switch is not cam operated, the switch installation should
permit over-travel during the homing sequence. The mechanism activating
the Home input switch might have considerable velocity upon initial
contact. The contact velocity is based on variables such as rate of
acceleration, command speed and distance from the Home position when
the HOME instruction is invoked.
In detail, the HOME instruction sequence is as follows:
(1)
Is the motor on the HME switch? If YES, go to (5).
(2)
Accelerate towards the HME switch.
(3)
Is the motor on the HME switch? If NO go to (2).
(4)
Decelerate to a stop, reverse direction.
(5)
Accelerate away from the HME switch.
(6)
Is the motor on the HME switch? If YES, go to (5).
(7)
Decelerate to a stop, reverse direction.
(8)
Move towards the HME switch at Base Velocity. (If Base Velocity
is zero, the move will occur at a velocity of 0.25 steps per
second; the slowest possible rate.)
(9)
Is the motor on the HME switch? If no, go to (8).
(10) Stop, reverse direction.
(11) Move away from HME switch at:
•
256 steps/second
(FULL STEP)
•
128 steps/second
(HALF STEP)
•
25 steps/second
(10 MICROSTEPS)
•
2 steps/second
(125 MICROSTEPS)
Or at Base Velocity, whichever is lower
(12) Is the motor on the HME switch? If YES, go to (11).
(13) Stop
motor.
The four different final speeds based on the drive resolution in (11) are to
guarantee that the motor will stop within one increment of motion of the
Home input switch opening. Be sure to set the base velocity high enough
to allow the motor to move off the switch in a reasonable time. For most
applications, 256 steps per second should be adequate.
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Summary of Contents for CN0170
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