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FLEX Ex 8 Output and HART Analog Modules
Publication
1797-IN003J-EN-P - August 2017
Power-up State Behavior
The system and modules use the Output Enable bit at system power-up. The
power-up state of the Output Enable bit is 0 and must be transitioned to 1
through application program control to initialize activity of a module’s
outputs.
Before the Output Enable bit is transitioned to 1, module outputs remain off.
Once the initial power-up and application-program control transitions the
Output Enable bit to 1, and module output activity begins, subsequent
transitions of the Output Enable bit by any source will cause the output
module to apply the local module fault state.
Cooperative Operation of the Adapter and the 1797-OE8H Output
Module
The 1797-OE8H module has more intelligence than the 1797-OE8 module.
The ControlNet adapter, the EtherNet adapter, and the FlexLogix controller
are aware of this. These adapters convey the Run/Program (Idle) Mode and
Communication Fault status directly to the 1797-OE8H module. The
1797-OE8H module monitors this information and determines its own fault
state actions according to your configuration. This allows for a more
simplified approach to your connections. With regard to the Program Mode
Behavior and Network Communication Fault, the 1797-OE8H module can
be configured to provide the following:
• Set Analog Output to Minimum Value
• Set Analog Output to Maximum Value
• Hold Last Analog Value
• Go to User Programmable Analog Value
• Set Digital Output to Minimum Value
• Hold Last Digital Value
IMPORTANT
After the 1797-OE8H module is powered up and prior to it
receiving its configuration information from the network, the
1797-OE8H will default its fault states to Set Analog Output
to Minimum Value and Set Digital Output to Minimum Value.