Allen-Bradley SLC 500 1746-NR4, User Manual

Page: 105 / 134

Chapter 7
Module Diagnostics and Troubleshooting
7–6
Figure 7.3
Troubleshooting Flowchart
An open–circuit or
short–circuit (RTD) condition
is present. Check channel
for open or loose
connections (RTD and
potentiometer inputs) and
check channel for
short–circuit condition (RTD
only). Retry.
Out–of–range error indicating
that either an over range or
under range condition exists.
For over range, the input
signal is greater than the
high scale limit for the
channel. For under range,
the input signal is less than
the low scale limit for the
channel. Correct and Retry.
End
Check LEDs
on module.
Module
Channel
blinking
Module fault
condition
Normal module
operation
Channel is
not enabled.
Channel is enabled
and working
properly.
Is problem
Check to see
that module is
seated properly
in chassis.
Cycle power.
corrected?
Contact your
local distributor
or
Allen–Bradley.
Yes
No
Check channel
status word
bits 13 – 15.
Bit 13
set (1)
Bit 14
set (1)
Bit 15
set (1)
Enable channel if
desired by setting
channel config.
word (bit 11 = 1).
Retry.
End
End
Fault
condition
Configuration error. Check
configuration word bits 0–3
for valid input type
configuration: bits 13 and
14 for valid scale select
setting: and bits 6 and 7 for
valid Broken Input select
setting. Retry.
Is problem
corrected?
Contact your
local distributor
or
Allen–Bradley.
No
Channel
Status LED is
on.
Channel
Status LED is
off.
Yes
Status LED is off.
Module
Status LED is on.
Status LED(s)
AB Spares