Deadband
This is the to lerance on the chilled water/ brine temperatu re
CONTROL POINT
. If the water
temperature goes out s ide of the
DEADBAND
, the PIC opens or closes t he guide vanes in
response until it is wit hin tolerance. The PIC may be configured with a 0.5° to 2° F (0.3° to
1.1° C) deadban d.
DEADBAND
may be viewed or modified on th e Equipment Service1 t abl e.
For example, a 1° F (0.6° C) deadba nd setting controls the wat er temperature within ±0.5° F
(0.3° C) of the control point . This may cause frequent gui de vane movement if the chille d water
load fluctuates frequ ently. A value of 1° F (0.6° C) is th e default setting.
Proportional Bands and Gain
Proportional band is th e rate at which the guide vane position is corrected in proportion to
how far the chilled water / brine temperature is f rom the control point. P r opo rtional gain
determines how quic k ly th e gui de vanes react to how quic k ly t he temperature is movi ng from
CONTROL POINT
.
The Proportiona l Band can be viewed/modified on t he LID. There are two resp onse modes,
one for temperature resp onse above the control po int, the other for respon se below the control
point.
The first type is called
PROPORTIONAL INC BAND
, and it can slow or quicken v an e
response to chilled wat er/brine temperatu r e abo ve
DEADBAND
. It can be adjusted from a
setting of 2 to 10; the defaul t setting is 6.5.
PROPORTIONAL DEC BAND
can slow or quicken