5
Chapter 3: SVI Modes
Modes
SVI functions in normal operating, manual operating, configuration, calibration, diagnostic and fail-safe
modes. The definitions of these SVI modes are:
•
Normal Operating Mode:
In this mode, the SVI controls the valve in responds to the 4-20 mA
input signal. When the built-in process controller is enabled and SVI is in normal mode,
the valve responds to the output of the process controller.
•
Manual Mode:
Both the controller setpoint and valve position can be adjusted manually using
ValVue and HART commands. When entering this mode, the SVI leaves the valve in the last
position after leaving Normal Operating Mode. The SVI will no longer respond to the 4-20 mA
input signal. When the built-in process controller is enabled, the output of the process controller
and valve position is fixed.
•
Configuration Mode:
In this mode, the valve remains in place and no longer responds to the
4-20 mA input signal. Configuration mode is used to display SVI configuration and modify the
configuration as necessary.
•
Calibration Mode:
In this mode, the valve no longer responds to the 4-20 mA input signal.
Calibration mode is used to scale and calibrate analog inputs, valve position, out pressure, and
tune the valve position control algorithm.
•
Diagnostic Mode:
Diagnostic mode allows the user to run several useful test procedures that
provide information on the valve and its performance.In this mode, the valve no longer responds
to the 4-20 mA signal. The valve may be stroked over a narrow or full range depending on the
type of test and parameters selected.
•
Failsafe Mode:
SVI does not go to failsafe mode if it is functioning normally. If a problem
occurs that causes the SVI to enter the failsafe mode, the SVI will attempt to drive the valve fully
open or fully closed, depending on the configuration settings.
Usually, SVI is in normal mode during operation. SVI may be switched from normal mode to manual
mode for manual manipulation of the valve. In manual mode, SVI may be switched back to normal
mode, or switched to configuration mode, calibration mode, or diagnostic mode. SVI may fail to the
failsafe mode in any mode when a predefined problem occurs.
Since some calibrate functions stroke the valve
over its full range, the valve should be isolated
from the process before moving to the Calibrate
Mode.
Since some diagnostic functions stroke the valve
over part or full range, the valve should be isolated
from the process before moving to the Diagnostics
Mode.
WARNING
WARNING
