Manual

7-12 Changing the Personality
Step Verify Options
49: Step Verify Control, range 0 to 3, factory 0
This parameter controls the behavior of the Step Verify option. Each bit has a specific
meaning, as follows:
Table 28 - Step Verify Control Value Definitions
Bit Dec. Value Meaning, if 1
0 1 If this bit is set then the Automove System suppresses the
automatic Emergency Stop at slip detection. The machine will
continue to execute motion commands after a slip is detected.
1 2 If this bit is set then the Step Verify circuit remains active while
the motor current is off. If any XY motion occurs due to
external forces the machine will enter the Motor Slipped state.
See the PM command.
50: Slip Response Download Sequence I.D., range -1 to 255, factory -1
If this parameter is in the range 0 through 255 it specifies the I.D. of a Download Sequence
which is to be automatically executed when the optional Step Verify circuit detects a slip
of the X or Y stepping motor. The Download Sequence is started after the automatic
Emergency Stop, if any. (See parameter 49, above.)
If parameter 50 is -1 then no Download Sequence is executed when a slip is detected.
The Slip Response Download Sequence executes in a privileged mode. Normally the
Automove System will not interrupt an interrupt. (See "Interrupting An Interrupt" in
Chapter 8.) The Slip Response Sequence is allowed to interrupt an interrupt (unless it
exceeds the maximum nesting depth) and cannot itself be interrupted by anything other
than another Slip Response sequence.
Note that when a slip is detected the machine may become Emergency Stopped. If the
automatic Download Sequence is to perform any physical action then it must first execute a
CS ("Clear Stop") command. The CS will automatically be delayed a few moments to
allow things to come to rest after the slip is detected, so that another slip will not be
immediately detected. (See parameter 51, below.)
Caution: Emergency Stop causes the XY position reference to be lost in unexpected
ways. You must execute an FH or SP command before attempting any
vectors or arcs after an Emergency Stop.
Use caution when designing automatic responses to motor slip. Be sure you have
considered all of the circumstances under which a slip might occur, and that your
automatic response isn't more destructive than the thing that caused the slip. Consider
whether another slip might occur during the response to a slip.
In general, the automatic response should be simple and brief. It should start with a CS to
clear the Slipped and Stopped states so that the Digital Outputs can be changed, and should
end with an AD ("Abort Download Sequence Execution") command. It is usually best to
call for operator intervention, perhaps by turning on a light or buzzer. Humans are much
better at "fixing things up" than machines!