Rockwell Automation 1746-NT8 SLC 500 Thermocouple/mV Analog Input Module User Manual - Manual (Page 78)

Publication 1746-UM022B-EN-P - January 2005
6-6 Troubleshooting Your Module
Troubleshooting Flowchart
End.
mV
End.
No
Yes
Bit 15
set 1
Bit 12
set (1)
Bit 14
set (1)
Bit 13
set (1)
Is problem
corrected?
No
Yes
Yes
No
End .
Yes
No
Thermocouple
Check LEDs
on module.
Module Status
LED(s) off.
Module Status
LED(s) off.
Channel
Status LED(s)
flashing.
Channel
Status LED(s)
off.
Channel
Status LED(s)
on.
Channel
is not enabled.
Channel
is enabled and
working.
Module fault
condition.
Normal
module
operation.
Fault
condition.
Enable channel if
desired by setting
channel config.
word (bit 0=1).
Retry.
Check to see that
module is seated
properly in
chassis. Cycle
power.
Are
faulted channel(s)
configured for mV
or thermocouple
input?
Is more than
one LED
blinking?
CJC fault has
probably
occurred.
Check channel
status words bits
12 through 15.
Check that wiring is secure
at both CJCs and that the
temperature within the
enclosure is in the range
limits of the CJC sensor.
Channel error. Check
configuration word bits 1
through 4 for valid input
type configuration and
ensure bits 12 through 14
are set to zero. Retry.
Over-range condition exists.
The input signal is greater
thank the high scale limit for
the channel or the CJC
connections. Corret and
retry.
Under-range condition
exists. The input signal is
less than the low scale limit
for the channel or the CJC
connections. Correct and
retry.
An open-circuit condition
is present. Check channel
and CJC wiring for open or
loose connections. Retry.
Contact your local
Allen-Bradley
distributor.
Contact your local
Allen-Bradley
distributor.
Contact your local
Allen-Bradley
distributor.
Is problem
corrected? Is problem
corrected?