Cutoffs And Limits; End Point Pressure Control; February - Fisher FIELDVUE DVC6200 Instruction Manual

Instruction Manual
D103605X012
D Fallback-Sensor/Tvl Deviation—The instrument will fallback to pressure control if a travel sensor failure is detected,
or if the Tvl Dev Press Fallback setting is exceeded for more than the Tvl Dev Press Fallback Time.
Note
Travel / Pressure Select must be set to Travel for double‐acting actuators

Cutoffs and Limits

D Hi Limit/Cutoff Select—When the Hi Cutoff/Limit Select is configured for Cutoff, the Travel Target is set to 123%
when the Travel exceeds the Hi Cutoff Point. When the Hi Cutoff/Limit Select is configured for Limit, the Travel
Target will not exceed the Hi Limit Point.
D Hi Limit/Cutoff Point—This is the point within the calibrated travel range above which the Limit or Cutoff is in effect.
When using cutoffs, a Cutoff Hi of 99.5% is recommended to ensure valve goes fully open. The Hi Cutoff/Limit is
deactivated by setting it to 125%.
D Lo Limit/Cutoff Select—When the Lo Cutoff/Limit Select is configured for Cutoff, the Travel Target is set to ­23%
when the Travel is below the Lo Cutoff Point. When the Hi Cutoff/Limit Select is configured for Limit, the Travel
Target will not fall below the Lo Limit Point.
D Lo Limit/Cutoff Point—This is the point within the calibrated travel range below which the Limit or Cutoff is in effect.
When using cutoffs, a Cutoff Lo of 0.5% is recommended to help ensure maximum shutoff seat loading. The Lo
Limit/Cutoff is deactivated by setting it to ­25%.
End Point Pressure Control (EPPC)
Note
End Point Pressure Control is available for instrument level ODV.
D EPPC Enable—Select Yes or No. End Point Pressure Control allows the digital valve controller to pull back from
saturation of the pneumatic output after reaching the travel extreme. Rather than having the instrument provide
full supply pressure (saturation) continuously at the travel extreme, the digital valve controller switches to an End
Point Pressure Control where the output pressure (pressure controller set point) to the actuator is maintained at a
certain value. This value is configured through the Upper Operating Pressure feature. Because the digital valve
controller is constantly in control and not allowed to reach a dormant or saturated state, it is constantly testing its
own pneumatic system. If there is an output pressure deviation, for example, the instrument will issue an alert. To
ensure there is an alert when an output pressure deviation occurs, setup the alert as described under Pressure
Deviation Alert.
Configuration

February 2017

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