User manual

Publication 1797-6.5.1 - April 1999
2-8 Understanding Configurable FLEX Ex Analog Module Features
Latch Retry Mode
Latch Mode determines channel operation under wire off or lead break fault
conditions. This feature controls the operation of two channel groups,
channels 0-3 and channels 4-7. 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.
Analog Digital State
You can configure your FLEX Ex analog I/O module to work in an analog
mode or digital mode using the Analog Digital State feature. Depending on
which state you choose for your application, additional parameters (see the
descriptions of Analog Fault State and Digital Fault State on page 2-9) must
be configured for your module to react to fault conditions.
Set the Analog Digital State bit in your programming software to 0 for your
module to operate in an analog state. Set the bit to 1 for your module to
operate in a digital state. A selection bit is available to each channel.