ADLINK PCI-8258 - Manual (Page 210)

196 Motion Control Theory
When software limit signal is set to ON status the controller
responses with following actions:
1. If SPEL signal is asserted for an axis in positive direction
motion status, the controller stops motion of the axis
immediately and error stop code of the axis is set to "6"
(STOP_SPEL) and motion status of axis is set to
abnormal stop (ASTP).
2. If SMEL signal is asserted for an axis in negative
direction motion status, the controller stops motion of the
axis immediately and error stop code of the axis is set to
"7" (STOP_SMEL) and motion status of axis is set to
abnormal stop (ASTP).
3. If the axis is not in motion status and the SPEL signal is
asserted then user's positive direction motion command
shall be ignored by the controller while error stop code of
the axis is set to STOP_SPEL (6) and motion status of
axis is set to abnormal stop (ASTP).
4. If the axis is not in motion status and the SMEL signal is
asserted then user's negative direction motion command
shall be ignored by the controller while error stop code of
the axis is set to STOP_SPEL (7) and motion status of
axis is set to abnormal stop (ASTP).
4.11.2.2 Position Error Protection
Position error protection is a software protection mechanism by
monitoring difference between command counter and feedback
counter. This difference is defined as position error. When position
error is too big, the controller sends a Servo off signal which can
be set up for use before servo fine tuning.
This function can be set up with axis parameters as shown in table
below. You can disable the position error protection by setting
position error parameter (PRA_ERR_POS_LEVEL) to value "0".
The position error protection is enabled when position error
parameter is set to non-zero value.
Position error protection causes the controller responses with
following actions:
If the position error value is greater than setting given by users,
the controller run Servo off command directly and error Stop code
of the axis is set to STOP_ERROR_LEVEL (6) and motion status
of axis is set to abnormal stop (ASTP).
NO Define Description
124h PRA_ERR_POS_LEVEL Position error protection setup