Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 66)

Installing the Assembly
Chapter 6
6Ć16
2. The 1771-M3 controller sends the hardware stop signal to the PC
data table thru the status block transfer.
3. After this circuit closes again, the 1771-ES expander still holds the
velocity command at zero and holds the servo drive disabled until
you either:
send a reset signal through a command block transfer (This allows
the 1771-ES controller to maintain the accumulated axis position.)
cycle I/O chassis backplane power off, then back on (This clears
the accumulated axis position.)
When you restart the axis after a hardware stop, the axis feedrate
accelerates before reaching the final velocity rate. This allows a smooth
start-up after a hardware stop.
Do not provide switch contacts in the hardware stop circuit for an
operator to turn off the axis motion. Opening the hardware stop circuit
stops the axis abruptly, stressing the servo drive, the servo motor, and the
mechanical linkage, just as the CRM would. Use the hardware stop input
only for backup to inform the 1771-ES expander of a condition that has
already stopped the axis so that the expander can provide a controlled
start-up.
Connecting Home Limit Switch
To connect a home limit switch, follow these steps:
1. Connect a normally open limit switch between the home limit switch
terminal and common.
2. Place the limit switch so that it closes as the axis reaches a point
approximately one half of an encoder revolution from the point you
want to establish as home position.
3. Adjust the angular position of the encoder to have the marker pulse
occur precisely at the point you want to establish as home position.
Through the command block transfer you can command a search home
function (sections titled “Axis Control Word” and “Axis Control Word
2”). The 1771-ES expander:
moves the axis to the limit switch
decelerates the axis