110
Rockwell Automation Publication 1794-UM061B-EN-P - March 2020
Appendix A
Interpret the Indicators
Diagnostic Functions for the 1794-OB16D
Diagnostic Functions for the 1794-OB16D
ATTENTION:
Each unused output port requires a dummy resistor
(20 k
+10%, 1/8 W) to mask the channel diagnostic function.
Ext.
Power
Wiring
Output
Status
Channel LED
Status
Open Wire
Error Bit
Short
Error Bit
Rev. Error
Bit
Module Error
Bit/LED
OFF
Open
Off
Off
0
0
0
0/OFF
On
Off
0
0
0
0/OFF
Short
Off
Off
0
0
0
0/OFF
On
Off
0
0
0
0/OFF
Normal
Off
Off
0
0
0
0/OFF
On
Off
0
0
0
0/OFF
ON
Open
Off
RED
1
0
0
1/RED
On
YEL
0
0
0
0/OFF
Short
Off
Off
0
0
0
0/OFF
On
RED
0
1
0
1/RED
Normal
Off
Off
0
0
0
0/OFF
On
YEL
0
0
0
0/OFF
REV
Open
Off
Off
0
0
1
1/RED
On
Off
0
0
1
1/RED
Short
Off
Off
0
0
1
1/RED
On
Off
0
0
1
1/RED
Normal
Off
Off
0
0
1
1/RED
On
Off
0
0
1
1/RED
The module monitors each output channel. It turns on the channel red indicator and sets (1) the error bit when 1) the module detects a
short circuit (the output signal is active at a channel and the corresponding output voltage is low), and 2) the module detects an open wire
(the output signal is inactive at a channel and the corresponding output voltage is high).