Rockwell Automation 1746-NR4 SLC RTD/Resistance Input Module User Manual - Manual (Page 100)

Publication 1746-UM008B-EN-P - December 2006
100 Module Diagnostics and Troubleshooting
A series of internal diagnostic self-tests is performed when power is
applied to the module. The module status LED indicator and all
channel status LED indicators remain off while power is applied. If
any diagnostic test fails, the module enters the module error state. If
all tests pass, the module status LED indicator is turned on and the
channel status LED indicator is turned on for the respective enabled
channel. The module continuously scans all enabled channels and
communicates with the SLC processor. During power up, the RTD
module does not communicate with the processor.
Power Turn-on Diagnostics When a channel is enabled (bit 11 = 1), a diagnostic check is
performed to see that the channel has been properly configured. In
addition, the channel is tested for out-of-range, open-circuit, and short
circuit faults on every scan.
Channel Diagnostics A failure of any channel diagnostic test causes the faulted channel
status LED indicator to blink. All channel faults are indicated in bits
13…15 of the channel’s status word. Channel faults are self-clearing
(bits 13 and 14 of status word). Bit 15 is not cleared until the you
make the correct change to the channel configuration. The channel
LED indicator stops blinking and resumes steady illumination when
the fault conditions are corrected.
LED Indicators The RTD module has five LED indicators. Four of these are channel
status LED indicators numbered to correspond to each of the
RTD/resistance input channels, and one is a module status LED
indicator.
LED Indicator Display
IMPORTANT
If you clear (0) a channel enable bit (11), all channel status
information (including error information) is reset (0).
0
1
2
3
INPUT
MODULE STATUS
CHANNEL
RTD/resistance
STATUS
Channel LED Indicators
Module Status LED Indicator