JOHNSON CONTROLS
53
SECTION 2 – OPTIVIEW CONTROL CENTER
FORM 160.79-O3
ISSUE DATE: 11/09/2018
2
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 Wait-
ing state and the Pre-rotation vanes position changes
by more than this value, the Probing state will be en-
tered. If the PRV Offset is set to 0%, the Stall Wait-
ing state is performed 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
(1-5 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.
Extreme Stall Duration
(10 to 20 minutes; default 10) – This setpoint applies
to both VGD controls. This setpoint specifies the maxi-
mum allowed time an extreme stall condition can exist
before the VGD operation is disabled and driven to the
full open (100%) position.
VGD 1
High Limit
(0.5-1.2 VDC; default 0.8) – Specifies the Stall Detec-
tor Board output voltage that represents an acceptable
amount of stall noise.
The minimum difference between the High Limit
setpoint and the Low Limit setpoint is 0.1 VDC. If a
Low Limit setpoint is entered which is less than 0.1
VDC below the High Limit setpoint, the High Limit
setpoint is adjusted so that it is 0.1 VDC above the
newly entered Low Limit value.
L
ow Limit
(0.4-0.8 VDC; default 0.6) – in the Stall Reacting State,
the VGD is driven closed until the Stall Detector Board
output voltage decreases to this level.
The minimum difference between the High Limit
setpoint and the Low Limit setpoint is 0.1 VDC. If a
Low Limit setpoint is entered which is less than 0.1
VDC below the High Limit setpoint, the High Limit
setpoint is adjusted so that it is 0.1 VDC above the
newly entered Low Limit value.
VGD 2
High Limit
(0.5-1.2 VDC; default 0.8) – Specifies the Stall Detec-
tor Board output voltage that represents an acceptable
amount of stall noise.
The minimum difference between the High Limit
setpoint and the Low Limit setpoint is 0.1 VDC. If a
Low Limit setpoint is entered which is less than 0.1
VDC below the High Limit setpoint, the High Limit
setpoint is adjusted so that it is 0.1 VDC above the
newly entered Low Limit value.
Low Limit
(0.4-0.8VDC; default 0.6) – in the Stall Reacting State,
the VGD is driven closed until the Stall Detector Board
output voltage decreases to this level.
