Emerson Fisher 4320 Instruction Manual page 37

4320 Position Monitor
October 2012
Description—enter a descriptor for the application with up to 16 characters. The descriptor provides a longer
user‐defined electronic label to assist with more specific instrument identification than is available with the HART tag.
Message—enter any message with up to 32 characters. Message provides the most specific user‐defined means for
identifying individual instruments in multi‐instrument environments.
Polling Address—used by the Host to identify a field device on the wired maintenance port (valid range is 0 through 63).
It has no significance on the wireless network and can only be edited at the maintenance port.
Structure
Switch State Properties and Set Point Properties—includes type, class, and connection information.
Note
Set Point Properties is only available for units equipped with the on/off control option.
Snap Acting Control—when enabled, control valve action is derived from the position feedback or position being
monitored. The controlled valve is separate from the position being monitored by the device. (There is no feedback
signal for the controlled equipment.) The state of the switch monitoring the sensor generates the command to the
controlled equipment.
Direct-Acting Snap—high or open trip on the input causes the controlled valve to open. Low or closed trip on the
input causes the controlled valve to close.
Reverse-Acting Snap—high or open trip causes the controlled valve to close. Low or closed trip causes the controlled
valve to open.
Adjust switch thresholds and deadband for additional refinement of this behavior. If the device is a controller and not
in snap-acting mode, it may not report the Process state or use a latching switch mode.
When snap-acting mode is disabled, the state of Snap-Acting Control is reported as "Feedback Control".
Note
Snap Acting Control is only available for units equipped with the on/off control option.
D Latching Mode—when enabled, any change to the specified switch state (either opened/high or closed/low) will be
latched (or locked) in that condition until the latch mode is manually reset. Latching mode is disabled when in
snap-acting mode.
Note
Latching Mode can only be used in a monitoring applications.
D Application Mode—indicates sensor reporting mode: process feedback or valve travel feedback. A device with the
controller option installed must report valve travel when not in snap-acting mode.
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Instruction Manual
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