Rockwell Automation 1794-OB16D FLEX I/O Diagnostic Modules User Manual - Manual (Page 33)

Publication 1794-UM061A-EN-P - July 2006
About the FLEX I/O Diagnostic Output Module 31
External Power Supply Reverse Voltage
If the external user power supply polarity is incorrect, the module is protected
and reports a reverse user voltage fault. The reverse voltage condition must be
at least -10V to detect a fault. The modules fault indicator turns red and the
reverse fault bit is set. The module error bit is also set. When the correct user
power supply polarity is applied, the module Fault indicator is off and the
reverse fault bit is not set.
User Power Supply Loss Detection
The module does not check for presence of the external user power supply.
You can detect user power loss by wiring any spare 24V dc input on a
1794-IB16D input module or 1794-IB16 input module to the power leads of
the power supply for the 1794-OB16D.
Output Fault & Idle States With Network Communication Failure
Configure module outputs for fault states, (either all on, all off or Hold Last
State), in the event of a network communication failure (fault state) or
switchover to Program mode (idle state). For example, if your module is
configured so that the state of the outputs turn off during Program (idle)
mode, any on-state outputs will turn off when in idle mode (processor
keyswitch placed in Program mode). Refer to documentation for your FLEX
I/O adapter and associated processor or controller for further information.
Indicator Status Information
The 1794-OB16D diagnostic output module has status indicators that allow
you to check the module health and operational status.
(1794-IB16D shown)