Controls; Definitions; Analog Signal; Discrete Signal - Carrier 19XRV Start-Up, Operation And Maintenance Instructions Manual

GUIDE VANE POWER PANEL CABLE
COOLER CHARGING CONTROL PANEL ACTUATOR CABLE
VALVE (HIDDEN)
WATER SEN_
CABLES
j cO2?s s'S 2
COOLER PRESSURE CABLE
TRANSDUCER
CONNECTION
/
SCHRADER
FITTING(HIDDEN)
CONDENSER
PRESSURE
TRANSDUCER
CONNECTION
CONDENSER CONDENSER
3-WAY SHUTOFF CHARGING
VALVE VALVE (HIDDEN)
COMPRESSOR
DISCHARGE
ELBOW JOINTS
Fig. 7 -- Chiller Controls and Sensor Locations
WATER
CABLES
CONTROLS
Definitions
ANALOG SIGNAL -- An analog signal varies in proportion
to the monitored source. It quantifies values between operating
limits. (Example: A temperature sensor is an analog device be-
cause its resistance changes in proportion to the temperature,
generating many values.)
DISCRETE SIGNAL --A discreW signal is a 2-position rep-
resentation of the value of a monitored source. (Example: A
switch produces a discrete signal indicating whether a value is
above or below a set point or boun&uy by generating an on/off.
high/low, or open/closed signed.)
General
--
The 19XRV herlnetic centrifuged liquid chiller
contains a microprocessor-based control panel that monitors
and controls all operations of the chiller (see Fig. 7). The
microprocessor control system matches the cooling capacity of
the chiller to the cooling load while providing state-of-the-art
chiller protection. The system controls cooling load within the
set point plus the deadband by sensing the leaving chilled water
or brine temperature and regulating the inlet guide vane via a
mechanically linked actuator motol: The guide vane is a
variable flow pre-whifl assembly that controls the refrigeration
effect in the cooler by regulating the amount of refrigerant
vapor flow into the compressor. An increase in guide vane
opening increases capacity. A decrease in guide vane opening
decreases capacity. The microprocessor-based control center
protects the chiller by monitoring the digital and analog inputs
and executing capacity overrides or safety shutdowns, if
required.
PIC III System Components -- The
chiller control
system is called the PIC 1II (Product Integrated Control [II).
See Table 1. The PIC III controls the operation of the chiller by
monitoring all operating conditions. The PIC III can diagnose a
problem and let the operator know what the problem is and
what to check. It promptly positions the guide vanes to
m_fint_fin leaving chilled water temperature. It can interface
with auxiliary equipment such as pumps and cooling tower
fans to turn them on when required. It continually checks all
safeties to prevent any unsafe operating condition. It also regu-
lates the oil heater while the compressor is off and regulates the
hot gas bypass valve, if installed. The PIC III controls provide
critical protection for the compressor motor and controls the
motor stmlel: The PIC III can interface with the Carrier
Comfort Network (CCN) if desired. It can communicate with
other PIC I, PIC II or PIC III equipped chillers and other CCN
devices.
The PIC [II consists of 3 modules housed inside 3 major
components. The component names and corresponding control
voltages are listed below (also see Table 1):
•
control panel
-- all extra low-voltage wiring (24 v or less)
• power panel
-- 115 vac control voltage (per job requirement)
-- 115 vac power for oil heater and actuators
-- up to 480 vac for oil pump power
• starter cabinet
-- chiller power wiring (per job requirement)
Table 1 -- Major PIC III Components and
Panel Locations*
PIC III COMPONENT
International Chiller Visual Controller
(ICVC) and Display
Chiller Control Module (CCM)
Oil Heater Contactor (1C)
Oil Pump Contactor (2C)
Hot Gas Bypass Relay (3C) (Optional)
Control Transformers (T1, T2, T3)
Temperature Sensors
Pressure Transducers
*See Fig, 5-10.
PANEL LOCATION
Control Panel
Control Panel
Power Panel
Power Panel
Power Panel
Power Panel
See Fig, 7.
See Fig, 7.
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