Cool Only Control - Brainchild C21 User Manual

4 - 2 Cool Only Control

4 - 2 Cool Only Control
A C91 is used to control a refrigerator at temperature below 0 C. The
temperature is lower than the ambient, a cooling action is required.
Hence select DIRT for OUT1. Since output 1 is used to drive a
magnetic contactor, O1TY selects RELY. A small temperature
oscillation is tolerable, hence use ON-OFF control to reduce the over-
all cost. To achieve ON-OFF control, PB is set with zero and O1HY is
B
set at 0.1 C.
Setup Summary: Setup Summary:
INPT=PT.DN INPT=PT.DN
L L
UNIT= C UNIT= C
DP=1-DP DP=1-DP
OUT1=DIRT OUT1=DIRT
O1TY=RELY O1TY=RELY
User Menu: User Menu:
PB = 0 ( C ) PB = 0 ( C )
O1HY=0.1 ( C ) O1HY=0.1 ( C )
Refrigerator
RTD
4
L L
3
L L
Figure 4.2 Figure 4.2
Cooling Control Example Cooling Control Example
UM0C911A
5 9
OP1 OP2
C F
SP1 SP2
PV MAN AT
R
C91
B
Mains Mains
Supply Supply
10
52