Positioner Error
The user may configure how position errors are handled. A position error occurs when the valve posi-
tion differs from the requested position by more than the Position Error Band for more than the position
error Time 1. When this occurs, a status flag is set which is reported during the next HART message.
The user must send a Read Status message to find out the cause of the status flag.
Care should be taken in selection of Time 2 to avoid un-necessary transitions to Fail Safe Mode. This
latter action may be enabled and disabled by checking and unchecking the check box.
For practical considerations, Position Error Band must be no less than 0.5% and no larger than 200%.
Time 2 (if enabled) must be larger than Time 1, and Time 2 must be no less than 5 seconds. Time 1
must be no less than 1 second or equal to -1 to disable the alarm function. Time 1 should be set at
least as long as the time required to fully open the valve from fully close or fully close the valve from
fully open. Otherwise, unnecessary position errors may be reported. The maximum time limit for both
Time 1 and Time 2 is 327 seconds.
Controller Page
SVI has a built-in process PID controller which is enabled only for SVI purchased with process controller
option. When Process Controller On is selected in Setup page, the Controller Tab in the SVI
Configuration window is enabled for basic process controller configuration.
For detail regarding the configuration of process controller, refer to Chapter 15: Controller Configuration.
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Enabling Time 2 may cause the valve to move to
its Failsafe position.
WARNING
Note:
Entering -1 in Time parameters disables the Position Error function.
