Pic System Functions - Carrier 17/19EX Start-Up, Operation And Maintenance Instructions Manual

PIC System Functions

Note: Throughout this manual, words printed in capital letters and italics are values that may be
viewed on the LID. See Table 2 for examples of LID screens. Point names are listed in
the Description column. An overview of LID operation and menus is given in
Figure 15, Figure
Capacity Control
The PIC controls the machine capacity by modulating the inlet guide vanes in response to
chilled water temperature changes away from the CONTROL POINT . The CONTROL POINT
may be changed by a CCN network device, or is determined by the PIC adding any active
chilled water reset to the chilled water SET POINT . The PIC uses the PROPORTIONAL INC
(Increase) BAND, PROPORTIONAL DEC (Decrease) BAND , and the PROPORTIONAL ECW
(Entering Chilled Water) GAIN to determine how fast or slow to respond. CONTROL POINT
may be viewed/overridden on the Status table, Status01 selection.
Entering Chilled Water Control
If this option is enabled, the PIC uses ENTERING CHILLED WATER temperature to
modulate the vanes instead of LEAVING CHILLED WATER temperature. ENTERING CHILLED
WATER control option may be viewed/modified on the Equipment Configuration table, Config
table.
16, Figure 17, Figure 18, Figure 19, and Figure
Figure 14,
20.