Honeywell LCBS User Manual

LCBS CONNECT SOLUTION
15 31-00118EFS—01
Fig. 5.
In cooling mode, the differential is above the set point. The output relay de-energizes when the temperature falls to the
set point. As the temperature rises to the set point plus the differential, the relay energizes. You will also see this referred
to as "reverse acting, where increased control action is in direct relationship to reduced temperature value.
Fig. 6.
Integral Action Primer and Refresher Course for Some
The purpose of the integral function is to eliminate the offset inherent in proportional control, in other words, integral
control functions to hold the input sensor value at set point.
The integral function is a function of proportional error and time.
When the proportional error is greater than 0 the integral error will be calculated and added to proportional error to
determine the control loop output. The integral error is cumulative and will continue to increase as long as the
proportional error is greater than 0. The increase in the output signal will drive the controlled device further open and the
controlled medium will be brought closer to set point. While the proportional error is reduced, the integral error will
continue to increase until the proportional error is eliminated.
PROPORTIONAL ON OFF CONTROL HEATING (REVERSE ACTING)
TYPICAL HEATING CIRCUIT
LOAD (HEATING) ON
“ERROR” =
SETPOINT PLUS
MEASURED
VALUE
HEATING
SETPOINT
“ON” WHEN “MEASURED VALUE” REACHES SETPOINT, OFF WHEN
“SETPOINT” PLUS “DIFFERENTIAL” EQUALS “MEASURED VALUE.”
REPEAT AS LOAD CHANGES.
LOAD (HEATING) OFF
MCR36699
LOAD
(HEATING) ON
PROPORTIONAL CONTROL – HEATING – REVERSE ACTING
MEASURED VALUE
“DIFFERENTIAL
PROPORTIONAL ON OFF CONTROL COOLING
(DIRECT ACTING) TYPICAL COOLING CIRCUIT
MEASURED VALUE
LOAD (COOLING) ON
LOAD (COOLING) OFF
“DIFFERENTIAL
“ERROR” =
SETPOINT
LESS
MEASURED
VALUE
COOLING
SETPOINT
PROPORTIONAL CONTROL – COOLING – DIRECT ACTING
“ON” WHEN “MEASURED VALUE” REACHES SETPOINT, OFF WHEN
“SETPOINT” LESS “DIFFERENTIAL” EQUALS “MEASURED VALUE.”
REPEAT AS LOAD CHANGES.
MCR36700

Honeywell LCBS Specifications

General

Brand	Honeywell
Model	LCBS
Category	Controller
Language	English