Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax User Manual

Page 44

5Ć2

Rotate the pulsetach in the forward direction. The

FORWARD LED on the module's faceplate should turn

on. Rotate the pulsetach in the reverse direction. The

REVERSE LED should turn on. If the LEDs do not turn on,

the module's pulse input circuitry is not working correctly.
If the pulsetach rotates 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.
Remove power from the rack and the pulsetach.

Reconnect the coupling between the motor and the

pulsetach. Reapply power to the system.

Step 4.

If external inputs are used, verify that the external input

circuitry is working correctly.
Toggle the external input device. Verify that the LED

associated with that particular bit (LATCH, COUNT STOP,

or CLEAR) is also toggling. If it is not, the external input

circuitry on the module is not working.
If the input triggers on the incorrect level (as specified in

with switch bounce. Care must be taken to eliminate any

switch bounce before the input. If switch bounce persists,

a proximity switch or photoelectric sensor with hysteresis

is recommended.

Step 5.

Verify that the module can be accessed.
Connect an IBMĆcompatible personal computer to the

system and load the Programming Executive software.

Refer to the AutoMax Programming Executive instruction

manual for more information.
Using the MONITOR I/O selection, monitor the external

input device and determine whether the bit is changing

state when toggled.
If you are able to read the input, the problem is in the

application task. Go to step 6. If the programming device

cannot read the inputs, the problem is in the hardware.

Go to step 8.

Step 6.

Verify that the I/O definitions are correct.
For modules in a local rack, the slot number must agree

with the slot that the module is actually in. Verify that the

module (M/N 57C416) must be located in the master rack

and connected via a coaxial cable to a slave Remote I/O

module located in the drop that contains the Pulsetach

Input module.
Verify that the master Remote I/O module is in the correct

slot. Next, verify that the drop number on the faceplate of

the slave Remote I/O module agrees with the drop

number being referenced in the task.
The slot number must agree with the slot that the module

is actually in. Verify that the register and bit number are

correct.