Vgd 2 - York YD Series Operation Manual

SECTION 2 – OPTIVIEW CONTROL CENTER
Time Remaining
Displays the time remaining in the "Probe Wait Time"
interval (value programmed as the Probe Wait Time
Setpoint) while the VGD is in the Stall Waiting State
or Surge waiting State.

VGD 2

Stall Detector Voltage
Displays the Stall Detector output voltage (x.xxVdc),
as received by the Microboard.
Pre-rotation Vanes Position
Displays the position of the Pre-rotation vanes over
the range of 0% (fully closed) to 100% (fully open).
Displayed as XXX until calibration procedure is per-
formed by Service Technician.
Variable Geometry Diffuser Position
Displays the position of the VGD over the range of 0%
(fully closed) to 100% (fully open). Displayed as XXX
until calibration procedure is performed by Service
Technician.
Diffuser Gap Close (LED)
Illuminates when a close signal is being applied to the
VGD.
Diffuser Gap Open (LED)
Illuminates when an open signal is being applied to the
VGD.
Surge Detected (LED)
Illuminates for 5 seconds each time a surge is detected.
Control Status
Displays the current state of the VGD control while the
chiller is running. The states are: Stall Waiting, Stall
Reacting, Probing, Surge Reacting, Surge Waiting, Hot
Gas Override, VGD Position Override, PRV Position
Override.
Time Remaining
Displays the time remaining in the "Probe Wait Time"
interval (value programmed as the Probe Wait Time
Setpoint) while the VGD is in the Stall Waiting State
or Surge Waiting State.
56
Programmable
PRV VGD Inhibit
(40% to 100%; default 90%). Applicable to dual com-
pressor operation only. Both VGD's will be pulsed
open according to the OPEN PULSE Setpoint as long
as both compressor's PRV's are above this value. While
this is in effect, "PRV Position Override" is displayed
as Control Status.
PRV Offset
(0-5%; default 3) – This setpoint applies to both VGD
controls. 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 Offset is set to 0%, the Stall Waiting state is per-
formed based only on the "Probe Wait Time" setpoint
interval.
Surge React
(1-30 seconds; default 5) – This setpoint applies to
both VGD controls. Specifies the length of the close
pulse applied to the VGD in response to a surge.
Probe Wait
(0.5-15 minutes; default 10) – This setpoint applies to
both VGD controls. Specifies how long the VGD con-
trol remains in the Stall Waiting or Surge Waiting states
before entering the Probing state.
Open Pulse
(1-9 seconds; default 2) – This setpoint applies to both
VGD controls. Specifies the length of the open pulse
applied to the VGD during 10 second periods while in
the Probing state.
Override Delta
(1% to 10%; default 5%) - This setpoint applies to both
VGD controls. This setpoint specifies the maximum
allowed difference (1% to 10%) between the Lead
VGD position and the Lag VGD position while the
VGD Position Override is in effect. The override starts
when the lag compressor pre-rotation vanes position
is greater than or equal to 80% of the lead compressor
pre-rotation vanes. While this override is in effect, if
the difference between the Lead VGD position and the
Lag VGD position is greater than the Override Delta
setpoint, the VGD with the higher position is driven
closed until it is within the allowed difference. "VGD
Position Override" is displayed as Control Status while
the override is in effect.
FORM 160.69-O1
ISSUE DATE: 9/30/2012
JOHNSON CONTROLS