York OPTIVIEW Operation Manual page 74

SECTION 2 - OPTIVIEW CONTROL CENTER INTRODUCTION
PROGRAMMABLE
Local Leaving Chilled Liquid Temperature -
Range
Access Level Required: OPERATOR
This is the range over which an analog signal (0-20
mA, 4-20 mA, 0-10VDC or 2-10VDC) in Analog Re-
mote Mode or a digital signal (PWM) in Digital remote
mode can reset the Leaving Chilled Liquid Tempera-
ture setpoint above the operator programmed Base Set-
point (see below). Programmable as either 10°F, 20°F,
30°F or 40°F, with a default of 10°F, it is added to the
BASE value to create a range over which the remote de-
vice can reset the setpoint. For example, if this setpoint
is programmed for 10°F and the operator programmed
value is 45°F, then the remote device can set the Leav-
ing Chilled Liquid Temperature setpoint over the range
45.0°F - 55.0°F.
Local Leaving Chilled Liquid Temperature -
Setpoint
Access Level Required: OPERATOR
This value allows the user to define the Leaving
Chilled Liquid Temperature that is to be maintained by
the chiller. It is programmable over the range of 38.0°F
to 70.0°F (water) or 10.0°F to 70.0°F (brine). If Smart
Freeze is enabled, the range is 36.0°F to 70.0°F (wa-
ter). A remote device can provide an analog signal (0-
20 mA, 4-20 mA, 0-10VDC or 2-10VDC) in Analog
Remote mode, or PWM signal in Digital Remote mode
that changes the setpoint by creating an offset above
the operator programmed Base Leaving Chilled Liquid
Temperature setpoint. This offset may be defined up to
10.0°F, 20.0°F, 30°F, or 40°F above the Base setpoint
(see the Remote Leaving Chilled Liquid Temperature
Setpoint Range description above). Additionally, E-
Link Gateway (in BAS Remote mode) can define the
setpoint through a serial data stream. In this case, the
incoming setpoint is not an offset that is applied to the
locally programmed Base setpoint value, but rather is
the setpoint value itself.
Leaving Chilled Liquid Temperature Cycling
Offset - Shutdown
Access Level Required: OPERATOR
This value allows the user to specify the Leaving
Chilled Liquid Temperature at which the chiller will
shut down on a LEAVING CHILLED LIQUID –
LOW TEMPERATURE cycling shutdown. This is
done by defining an offset below the Leaving Chilled
Liquid Temperature setpoint. It is programmable over
74
a range of 1°F to 64°F below the setpoint, to a mini-
mum cutout of 36°F (water), 34°F (water with Smart
Freeze enabled) or 6°F (brine). It establishes the mini-
mum allowed temperature for the Leaving Chilled
Liquid Temperature and prevents over-cooling of the
building. Anytime the Leaving Chilled Liquid Tem-
perature setpoint is increased, the shutdown threshold
is 36.0°F (water) or 6.0°F (brine) for the next ten (10)
minutes. If Smart Freeze is enabled, the threshold is
34.0°F for the next 10 minutes. After ten (10) minutes
have elapsed, the shutdown threshold becomes the pro-
grammed setpoint value.
Leaving Chilled Liquid Temperature Cycling
Offset - Restart
Access Level Required: OPERATOR
This value allows the user to specify the Leaving
Chilled Liquid Temperature at which the chiller will
restart after a shutdown on a LEAVING CHILLED
LIQUID – LOW TEMPERATURE cycling shut-
down. This is done by defining an offset above the
Leaving Chilled Liquid Temperature setpoint. It is
programmable over a range of 0°F to 70°F above the
setpoint, to a maximum restart value of 80°F. The
chiller will automatically restart when this temperature
is reached. This setpoint can be used to reduce chiller
cycling by delaying the chiller restart until the cooling
load has increased.
Remote Analog Input Range
Access Level Required: OPERATOR
This setpoint defines, for the control center, the re-
mote signal range applied for remote reset of the Leav-
ing Chilled Liquid temperature Setpoint and Current
Limit Setpoint in ANALOG remote mode. If the re-
mote signal is 0-10VDC or 0-20mA, this setpoint must
be programmed for 0-10VDC. If the remote signal
is 2-10VDC or 4-20mA, this setpoint must be pro-
grammed for 2-10VDC.
Local Input Current Limit
Access Level Required: OPERATOR
Allows the user to specify the maximum allowed chill-
er input current (as a percentage of FLA). When the
chiller input current reaches this value, the input cur-
rent override takes effect. When the unit is operated via
BAS (ISN) control mode the ISN current limits will
override the pulldown demand limit and current limit
set points. It is assumed that the BAS algorithms will
reset current limits as required.
FORM 160.78-O2
ISSUE DATE: 5/22/2017
JOHNSON CONTROLS