Technical Specifications

629
Configure Tab
Button Lock The SVI comes with an optional local display and buttons for data
entry. These buttons can be used to perform basic SVI setup with-
out the need for ValVue or a handheld. It may, however, be desir-
able after initial setup to lock the buttons so that the SVI
parameters cannot be inadvertently changed from the buttons.
Several levels of locks are provided:
 Allow Local Buttons (level 3): Buttons on the SVI are enabled.
 Lock Out Local Cal. - Config. (level 2): You can use the
buttons to perform operations in normal operating mode
and manual mode, however they may not go to configure
or calibrate mode.
 Lock Out Local Manual (level 1): You can examine variables
in normal operating mode but may not put the valve in
manual mode (and therefore cannot get to calibrate or
configure modes).
 Lock Out All Buttons (level 0): The buttons are disabled.
Bumples s Transfer This option provides a means to maintain smooth valve control
positioning when changing to Normal mode from Manual or Setup.
Without Bumpless Transfer, when changing to Normal mode, the
setpoint could vary in a manner that causes a significant process
disturbance. Bumpless Transfer moves the controller signal to
match the valve position so that smooth resumption of control
with little disturbance results.
When Bumpless Transfer is selected, returning to Normal mode
from Manual or Setup mode is deferred until the input signal
matches the current valve position. Either the input signal or the
valve position can be changed to match. If nothing is done, the sys-
tem slowly changes the position until it matches the signal set-
point. The time taken to move to the position is determined by the
Transfer Time which is a number between 0 and 255 and is
approximately the number of seconds required to move the valve
100%.
Near Closed The Near Closed value determines the value of position below
which the valve is considered near closed by the continuous diag-
nostic calculations.
Tight Shutoff When selected, if the input signal of the valve would position the
valve below the tight shutoff value (entered in the edit box to the
right), full supply pressure or atmosphere pressure is supplied to
the actuator as needed to close the valve with full seating force.