Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax - Manual (Page 18)

3Ć4
Monitor the counter register and rotate the pulsetach.
Verify that the counter register counts in the proper
direction. If the pulsetach rotates in the wrong direction,
which causes the counter register to count in the wrong
direction, the pulsetach input wires must be switched. In
a singleĆended wiring configuration, swap the A and B
inputs. In a differential wiring configuration, swap the A
and not A inputs.
Step 12. Turn off power to the rack and pulsetach. Connect the
mechanical coupling between the motor and the
pulsetach. Turn on power to the system.
3.3 Module Replacement
Use the following procedure to replace a module:
WARNING
INSERTING OR REMOVING A MODULE OR ITS CONNECTING CABLES MAY
RESULT IN UNEXPECTED MACHINE MOTION. TURN OFF POWER TO THE RACK
BEFORE INSERTING OR REMOVING A MODULE OR ITS CONNECTING CABLES.
FAILURE TO OBSERVE THESE PRECAUTIONS COULD RESULT IN BODILY
INJURY.
Step 1. Turn off power to the rack, pulsetachs, and field wiring.
Step 2. Use a screwdriver to loosen the screws holding the cable
assembly's (M/N 57C372) field wiring connector to the
module. Remove the cable connector from the module.
Step 3. Loosen the screws that hold the module in the rack.
Remove the module from the slot in the rack.
Step 4. Place the module in an antiĆstatic bag, being careful not
to touch the connectors on the back of the module. Place
the module in the cardboard shipping container.
Step 5. Take the new module out of the antiĆstatic bag it came in.
Be careful not to touch the connectors on the back of the
module.
Step 6. Insert the module into the desired slot in the rack. Use a
screwdriver to secure the module into the slot.
Note that if you are replacing a 57421Ć1 module with a
57C421A or later module, you must add the three
jumpers shown in figure 3.4 to the terminal strip of the
replacement module in order for the module to operate
properly. (Jumper from terminal 14 to terminal 17, and
jumper from terminal 17 to terminal 20.)
If you were using a 57421Ć1 module with 5 V differential
inputs, you must write a zero into bit 11 of register 6. Bit
11 is no longer required to select differential inputs. Bit 11
now selects the polarity of the Zpulse.
Step 7. Attach the cable assembly's field wiring connector to the
mating half of the connector on the module. Use a
screwdriver to secure the connector to the module.
Step 8. Turn on power to the rack, the pulsetach, the motor, and
the field wiring.