4.9 Software Limits
4-41
Feed Axis
Operation
4.9
Software Limits
Software limits are used to set upper and lower limits for the range of machine movement so that the host con-
troller can constantly monitor the operating range of the machine. Software limits can be used to help prevent
machine runaway or damage due to incorrect operation or errors in a motion program.
To implement software limits, the reference and feedback positions must constantly be monitored from the
host controller. Monitor the reference position (the position reference (CPOS) to the SERVOPACK) and check
whether the upper and lower software limits are exceeded to ensure safe operation of the machine.
Perform the processes according to the following flowchart to implement the software limits on the host con-
troller.
(1) Reference Position Confirmation
Compare the position reference value that is sent to the SERVOPACK and the upper and lower software limits
to make sure the upper and lower software limit values are not exceeded.
Monitor the position reference value regardless of the operation status of the axis.
However, if the origin has not been set, the mechanical origin will not yet be established. Do not monitor the
position reference value in this case.
Motor
Reverse
overtravel
Lower software
limit
Machine movement range
Forward
overtravel
Upper software
limit
NO
YES
YES
NO
START
Servo ON
Axis movement
(operation)
Is the overtravel P-OT
= 1 or N-OT = 1?
Send a position reference to stop the
axis at a specified deceleration rate
(stop the axis with the INTERPO-
LATE (34 hex) command).
Confirm that the axis
has stopped.
Perform processing to return
the axis (move the axis in the
opposite direction).
Has the axis returned?
END