Pressure Control; Pressure Fallback - Fisher FIELDVUE DVC6200 Instruction Manual

Configuration
February 2017
D EPPC Set Point—Used in conjunction with End Point Pressure Control, End Point Pressure Control Set Point allows
the user to select a pressure to be delivered by the instrument at the travel extreme. For a fail‐closed valve, this
pressure must be sufficient to maintain the fully open position. For a fail‐open valve, this pressure (which is
automatically set to supply pressure) must be sufficient to fully close the valve and maintain its rated shutoff
classification. For double‐acting spring return actuators, this is the differential pressure required to either maintain
the fully open or fully closed position, depending on the valve and actuator configuration. For a double‐acting
actuator without springs with a fail‐close valve, this is 95% of the supply pressure. If the valve is fail‐open, the upper
operating pressure for all actuator is set to the supply pressure.
D EPPC Saturation Time—End Point Pressure Control Saturation Time is the time the digital valve controller stays in
hard cutoff before switching to pressure control. Default is 45 seconds.

Pressure Control

D Pressure Range High—The high end of output pressure range. Enter the pressure that corresponds with 100% valve
travel when Zero Power Condition is closed, or 0% valve travel when Zero Power Condition is open. This pressure
must be greater than the Pressure Range Lo.
D Pressure Range Lo—The low end of the output pressure range. Enter the pressure that corresponds to 0% valve
travel when Zero Power Condition is closed, or 100% valve travel when Zero Power Condition is open. This pressure
must be less than the Pressure Range Hi.

Pressure Fallback

Note
Pressure Fallback is available for instrument level AD, PD, ODV.
D Tvl Dev Press Fallback—When the difference between the travel target and the actual travel exceeds this value for
more than the Tvl Dev Press Fallback Time, the instrument will disregard the travel feedback and control based on
output pressure.
D Tvl Dev Press Fallback Time—This is the time, in seconds, that the travel target and the actual travel must be
exceeded before the instrument falls back into pressure control.
D Fallback Recovery—If the instrument has fallen into pressure control and the feedback problem is resolved, recovery
to travel control can occur automatically or with manual intervention. To return to travel control when Manual
Recovery is selected, change the Fallback Recovery to Auto Recovery, and then back to Manual Recovery (if
desired).
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Instruction Manual
D103605X012