Rockwell Automation 1797-OE8H FLEX Ex HART Analog Modules User Manual - Manual (Page 37)

Publication 1797-6.5.3 - March 2006
Understand Configurable FLEX Ex Analog Module Features 2-7
Selecting a 1797-OE8H FLEX
Ex Analog Output Module’s
Operating Features All features of the 1797-OE8H analog output module are independently
configurable in two four-channel groups (channels 0 to 3 & channels 4 to 7).
Local Fault Mode
The Local Fault Mode can be programmed to determine how the module
responds to communications faults and internal module faults.
When setting the Local Fault Mode feature in your programming software, set
this feature’s bit to 0 to use the analog fault state or digital fault state only if a
communications fault occurs. Set the bit to 1 to use the analog fault state or
digital fault state if any fault occurs.
Latch Mode
Latch Mode determines channel operation under wire off or lead break fault
conditions. This feature controls the operation of two channel groups,
channels 0 to 3 and channels 4 to 7. Channel detection occurs on a continuous
basis. If a fault is detected, the channel fault alarm is set.
If Latch Mode is enabled when a fault occurs, the fault will remain latched in
its fault state until a Global Reset (see below) is issued. If Latch Mode is
disabled when a fault occurs, the channel reports a fault until the fault is
corrected. Global Reset is not necessary if Latch Mode is disabled.
When using your programming software, set the Latch Mode bit to 0 to
disable the feature. Set the bit to 1 to enable it.
Global Reset
Global Reset works in conjunction with Latch Mode during fault conditions. If
Latch Mode is enabled and a fault condition occurs, the channel operating with
a fault remains in this condition (with analog or digital fault state implied) until
a Global Reset is issued. The Global Reset feature resets all outputs of a
particular channel group to accept normal system output data.
The Global Reset feature is an edge triggered signal. Use your programming
software to set the Global Reset bit to 1 for normal operation. Resetting of
outputs occurs during the 1 to 0 transition.
IMPORTANT
The default selection value for all parameters is 0.