Rockwell Automation 1797-OE8H FLEX Ex 8 Output Analog Modules - Manual (Page 31)

FLEX Ex 8 Output and HART Analog Modules 31
Publication 1797-5.3 - September 2011
Cooperative Operation of the ControlNet Ex Adapter and the
1797-OE8 Output Module
The ControlNet Ex adapter (1797-ACNR15) combined with the 1797-OE8
output module provides a two-tier fault state mechanism. It is important to
consider and understand the operation of this mechanism when designing
your system.
Two sets of programmable fault states are available, one each in the adapter
and 1797-OE8 module. This two-tier method is meant to give you a wider
fault coverage compared with normal methods.
Adapter Operation with the 1797-OE8 Module
Network Communication Monitoring
The adapter is the primary monitor of network activity. If it detects loss of
network communication, it can be configured to:
• continue writing the last valid received data to the module (hold last
state).
• apply local module safe states.
(1)
• write a programmable fault state value to the module, depending upon
the module type.
(2)
This mechanism primarily targets fault behavior for loss of network
communication.
(1) This selection could be shown as Reset Outputs but its action is Apply Local Module Safe States.
(2) This option is only available in some adapters.