Troubleshooting A Digital Input Module - Hitachi HSC-2100 Hardware Manual

6.2.3 Troubleshooting a digital input module

Case 1 -- none of the input points is turned on:
Not
Operation
lit
indicator
LED
condition
Lit
None of the above
Case 2 -- a particular input point(s) are not turned on:
Operation
Not
indicator
lit
LED
condition
Lit
None of the above
Case 3 -- all of the input points are always turned on:
Operation indicator LED not lit
Operation indicator LED lit
Check item
Terminal block attached
improperly
Module fixing-screws
loosened
External power source not
supplying power
Power supply module's output
voltage abnormality
External wiring incorrect
Remote I/O station module's
operation abnormality
Check item
External input's on-state
duration too short
Wiring loosened or wire
breakage
Program I/O address error
Check item
Attach the terminal block properly to the
module.
Apply additional tightening to the fixing
screws.
Supply power from the external power
source.
Check the output voltage across the check
terminals of the power supply module.
Wire the module correctly.
Troubleshoot the remote I/O station
module according to the instructions given
in Subsection 6.2.2.
Replace the digital input module with a
new one.
Adjust the external equipment.
Wire the digital input module correctly.
Corrent the erroneous address.
Replace the digital input module with a
new one.
Replace the digital input module with a
new one.
Check the external wiring of the digital
input module for error.
If the wiring is correct, replace the module
with a new one.
6-7
6 MAINTENANCE
Remedial action
Remedial action
Remedial action