Rockwell Automation 1746-NI16V SLC 500 Analog Input Modules User Manual - Manual (Page 73)

Publication 1746-UM001A-US-P
Module Diagnostics and Troubleshooting 6-3
Open-Circuit Detection
An open-circuit test is performed on all enabled channels configured
for 4 to 20 mA input and all enabled channels with voltage
configurations. Whenever an open-circuit condition occurs, the
channel status LED blinks and the condition is reported in bits 15
through 13 of the channel status word. See “Error Codes” on page 6-5.
Possible causes of an open-circuit include:
•
The sensing device may be broken.
•
A wire may be loose or cut.
•
The sensing device may not have been installed on the
configured channel.
If an open circuit is detected, the channel data word reflects input
data as 0 mA in the 4 to 20 mA configuration. For the voltage module,
open-circuit data is displayed for all voltage ranges as the maximum
value readable in that voltage range. See tables on pages 5-9 and 5-10.
LED Indicators The module has five LEDs. Four of these are channel status LEDs
numbered to correspond to each of the four groups of four input
channels (0 to 3, 4 to 7, 8 to 11, 12 to 15). The fifth is a module status
LED.
INPUT
Channel Status LEDs
Module Status LED
0-3 4-7
8-11 12-15
Analog Voltage
Module Status
Channel Status