Specifications

40
PIC II System Functions — Refer to ICVC Opera-
tion and Menus section on page 17.
NOTE: Words not part of paragraph headings and printed in all
capital letters can be viewed on the ICVC (e.g., LOCAL,
CCN, RUNNING, ALARM, etc.). Words printed both in all
capital letters and italics can also be viewed on the ICVC and
are parameters (CONTROL MODE, TARGET GUIDE VANE
POS, etc.) with associated values (e.g., modes, temperatures,
pressures, percentages, on, off, enable, disable, etc.). Words
printed in all capital letters and in a box represent softkeys on
the ICVC (e.g., and ). See Table 3 for exam-
ples of the type of information that can appear on the ICVC
screens. Figures 15-21 give an overview of ICVC operations
and menus.
ALARMS AND ALERTS — An alarm shuts down the com-
pressor. An alert does not shut down the compressor, but it no-
tifies the operator that an unusual condition has occurred. An
alarm (*) or alert (!) is indicated on the STATUS screens on the
far right field of the ICVC display screen.
Alarms are indicated when the control center alarm light (!)
flashes. The primary alarm message is displayed on the default
screen. An additional, secondary message and troubleshooting
information are sent to the ALARM HISTORY table.
When an alarm is detected, the ICVC default screen will
freeze (stop updating) at the time of alarm. The freeze enables
the operator to view the chiller conditions at the time of alarm.
The STATUS tables will show the updated information. Once
all alarms have been cleared (by pressing the softkey), the de-
fault ICVC screen will return to normal operation. An alarm
condition must be rectified before a RESET will be processed.
However, an alert will clear automatically as soon as the asso-
ciated condition is rectified.
The CCN point EMERGENCY STOP is found at the end of
the MAINSTAT SCREEN. Whenever this point is forced to a 1
the chiller will stop and the following alarm will be generated:
250->Emergency Override/Stop. The EMERGENCY STOP
can be forced from anywhere and will be honored whether the
chiller is running or not and in CCN, LOCAL or STOP modes.
ICVC MENU ITEMS — To perform any of the operations
described below, the PIC II must be powered up and have suc-
cessfully completed its self test. The self test takes place auto-
matically, after power-up.
Press the MENU softkey to view the list of menu structures:
STATUS, SCHEDULE, SETPOINT, and SERVICE.
• The STATUS menu allows viewing and limited calibra-
tion or modification of control points and sensors, relays
and contacts, and the options board.
• The SCHEDULE menu allows viewing and modification
of the local and CCN time schedules and Ice Build time
schedules.
• The SETPOINT menu allows set point adjustments, such
as the entering chilled water and leaving chilled water
setpoints.
• The SERVICE menu can be used to view or modify
information on the Alarm History, Alert History, Control
Test, Control Algorithm Status, Equipment Configura-
tion, ISM Starter Configuration data, Equipment Service,
Time and Date, Attach to Network Device, Log Out of
Network Device, and ICVC Configuration screens. For
more information on the menu structures, refer to Fig. 18
and 19.
Press the softkey that corresponds to the menu structure to
be viewed STATUS, SCHEDULE, SETPOINT, or SERVICE.
To view or change parameters within any of these menu
structures, use the and softkeys to scroll down to the desired
item or table. Use the softkey to select that item. The softkey
choices that then appear depend on the selected table or menu.
The softkey choices and their functions are described below.
BASIC ICVC OPERATIONS (Using the Softkeys) — To
perform any of the operations described below, the PIC II must
be powered up and have successfully completed its self test.
Force priority
— The forces from various sources apply in an
order of priority. Any force can override a force with a lower
priority. The lowest priority belongs to the normal operating
control. A higher force cannot be overridden. For example, a
Service Tool force cannot be overridden by anything but a ma-
chine safety or fire alarm. See Table 4.
FLOW DETECTION — Flow detection for the evaporator
and condenser is (a) a required condition for startup, and (b)
used in the freeze protection safety.
Flow and no flow conditions are detected from a combina-
tion of several measurements. The usage of water side differen-
tial pressure measurements is not standard.
Positive determination of flow on the evaporator side is
made if the following conditions are true: (1) the EVAPORA-
TOR REFRIGERANT LIQUID TEMP reads higher than 1° F
(0.6° C) above the EVAPORATOR REFRIGERANT TRIP-
POINT, and (2) EVAPORATOR SATURATION TEMPERA-
TURE (determined from the Evaporator Pressure sensor) is
greater than the EVAPORATOR REFRIGERANT TRIP-
POINT. (If when the unit is in Pumpdown or Lockout mode,
conditions (1) and (2) are not required to establish flow.) On
the condenser side, positive determination of flow is made if
the following conditions are true: (1) the CONDENSER
PRESSURE is less than 165 psig (1139 kPa), and (2) CON-
DENSER PRESSURE is less than the configured CONDENS-
ER PRESSURE OVERRIDE threshold by more than 5 psi
(34.5 kPa). In addition, if the water side differential pressure
measurement option is enabled, the water side pressure differ-
entials (cooler and condenser) must exceed their respective
configured cutout thresholds.
Table 4 — CCN Force Priority Hierarchy
NOTE: Not all apply to chillers.
ENTER
EXIT
LEVEL NAME DESCRIPTION
1 FIRE Fire Alarm
2 SAFETY Machine Safety
3 SERVCE Service Tool Access
4 SUPVSR Supervisor or LID/ICVC
5 MONITR Offsite Building Supervisor or ComfortWorks
6 MINOFF Minimum on/off time
7 CONTROL Typically 3
rd
party access via interface
8 BEST BEST control from FIDs and comfort controllers
9 TEMP Temperature Override (thermostat type function)
10 LOAD Loadshed for demand limit/shedding load