JOHNSON CONTROLS
87
SECTION 2 – OPTIVIEW CONTROL CENTER
FORM 160.69-O1
ISSUE DATE: 9/30/2012
2
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 re-
mote mode can reset the Leaving Chilled Liquid Tem-
perature setpoint above the operator programmed Base
Setpoint (see below). Programmable as either 10°F or
20°F, with a default of 20°F, it is added to the BASE
value to create a range over which the remote device
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 de-
fined up to 10.0°F or 20.0°F above the BASE setpoint
(see the Remote Leaving Chilled Liquid Temperature
Setpoint Range description above). Additionally, Mi-
croGateway (in ISN 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 a range
of 1°F to 64°F below the setpoint, to a minimum cut-
out of 36°F (water), 34°F (water with Smart Freeze
enabled) or 6°F (brine). It establishes the minimum
allowed temperature for the Leaving Chilled Liquid
Temperature and prevents over-cooling of the build-
ing. Anytime the Leaving Chilled Liquid Temperature
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 programmed
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 shutdown.
This is done by defining an offset above the Leaving
Chilled Liquid Temperature setpoint. It is program-
mable 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 Chiller Current Limit
Access Level required:
OPERATOR
Allows the user to specify the maximum allowed Chill-
er Current during the Chiller Steady State Period (this
period is in effect after the Chiller Pulldown Period is
no longer in effect). Refer to the Electro-mechanical
Starter Screen for a detailed explanation of the Local
Chiller