Rockwell Automation 1746-HSTP1 Stepper Controller Module/ User Manual - Manual (Page 60)

Publication 999-121 - December 1999
Configuration and Programming 5-25
Notes:
1. When set, bit 3 (external interrupt) indicates that the Module has
initiated a controlled stop, only during a jog operation. The
stepper motor decelerates to the programmed starting speed,
and then stops. The current position information is retained.
2. When set, bit 2 indicates an external pulse train enable/disable
function has occurred. This identifies an uncontrolled stop, in
which normal deceleration did not occur and axis position data
is lost. This bit is set when a command is applied to input
terminal 11 on the front panel of the module.
3. When set, bit 8 indicates that either the system has detected the
wrong proximity to home switch sequence (i.e., proximity
switch detected after already reading a transition on the home
switch), or two different overtravel limit switches have been
detected during a home operation.
Input Words 2 and 3
Input words 2 and 3 report current position data, based on the
number of pulses that have been sent to the stepper motor. Note that
this value may be different from the encoder value in words 4 and 5.
Input Words 4 and 5
Input words 4 and 5 report the axis position based on either feedback
from an optional encoder attached to the stepper motor or diagnostic
feedback when configured. Note that this value may be different from
the current position in words 2 and 3. The value has a range of
±8,388,607 counts, equalling the limits of the Module. The optical
encoder values must be mechanically coupled to the motor. The
optical encoder values are not updated to the SLC backplane unless a
command is issued to the translator. Encoder direction values may be
independent of the motor direction, e.g. motor direction may be the
plus direction while encoder values decrease. The optical encoder
values do not change unless the stepper motor is turning. It is
possible for the encoder values to be increasing or decreasing
independently of the direction of motor rotation.
Diagnostics Feedback Test To perform a diagnostic feedback test, the Module must be configured
for diagnostic feedback, using the loop back feature, and pulse and
direction output. The external DC power supply must also be active,