York OPTIVIEW Operation Manual page 51

FORM 160.78-O2
ISSUE DATE: 5/22/2017
Low Limit
In the Stall Reacting State, the VGD is driven closed
until the Stall Detector Board output voltage decreas-
es to a threshold determined from this level. (0.30-
0.80VDC; default 0.45)
The minimum difference between the High Limit
setpoint and the Low Limit setpoint is 0.1VDC. If
a Low Limit setpoint is entered which is less than
0.1VDC below the High Limit setpoint, the High Limit
setpoint is adjusted so that it is 0.1VDC above the new-
ly entered Low Limit value.
VGD Count
Access Level Required: ADMIN
Allows the user to clear the VGD Cycle Count.
PRV VGD Inhibit - Gas Path Revision "A" Only
If PRV position exceeds this value, the VGD is pulsed
open according to the open pulse setpoint, and does
NOT respond to the stall detector voltage. Normal con-
trol resumes at or below this position. (40% to 100%,
default 95%)
JOHNSON CONTROLS
SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
PRV Offset - Gas Path Revision "A" Only
If the VGD control is in the Stall Waiting state and the
Pre-rotation vanes position changes by more than this
value, the Probing state will be entered. If the PRV Off-
set is set to 0%, the Stall Waiting state is performed
based only on the "Probe Wait Time" setpoint interval.
(0-5%; default 3)
VGD Start Position
Sets the position the VGD is set to for the beginning of
chiller run.
NAVIGATION
Home
Causes an instant return to the Home Screen.
VGD
Access Level Required: SERVICE
Causes an instant return to the Variable Geometry Dif-
fuser Screen.
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