Delta Computer Systems TMC 188/40 Series Manual page 42

Motion Control Parameters
4) When the HOME position is located, the axis extends 100 encoder counts from
HOME and the AT COMMAND POSITION bit is set.
If a limit or obstruction is found, the axis reverses direction.
If the axis is between a limit and an obstruction (i.e., caught between the limit switch and the
physical limit of the system) the axis is moved beyond the limit away from the obstruction.
If SPEED is set to 0 and an „@‟ command is issued, only the hardware counters are
changed; they are loaded with the preset value defined by:
Preset Value = (REQUESTED POSITION - OFFSET) x SCALE
rather than the default value of 100.
The „@‟ routine can be terminated at any time with the „Z‟ command.
NOTE: When an „@‟ command is given, the ladder logic program should use a timer to make sure
the HOME position is found within a reasonable amount of time. If HOME is not found
within the programmed time, stop the axis with a 'Z' command.
The external HOME input causes the counters to be loaded with the preset value determined
from the last „@‟ command. If a new SCALE or OFFSET is issued with a „P‟ command, an
„@‟ command must be issued to update the preset value of the external HOME.
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TMC 188/40 Motion Control Module
1000
Delta Computer Systems, Inc. 360/254-8688