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Chapter 4 Applications
4–1 Heat Only Control with
Dwell Timer
An oven is designed to dry products at 150°C for
30 minutes and then stay unpowered for another
batch. A TEC-920 equipped with dwell timer is
used for this purpose. The system diagram is
shown at right:
To achieve this function, set the following parame-
ters in the setup menu:
INPT=K_TC UNIT=°C
DP=1_DP OUT1=REVR
O1TY=RELY CYC1=18.0
O1FT=BPLS OUT2=TIMR
O2FT=ON
Auto-tuning is performed at 150°C for a new oven.
4–2 Cool Only Control
A TEC-920 is used to control a refrigerator at temperatures
below 0°C. This temperature is lower than the ambient, so a
cooling action is required. Select DIRT for OUT1. Since output
1 is used to drive a magnetic contactor, the O1TY should be set
for RELY. A small temperature oscillation is tolerable, so use
ON-OFF control to reduce the over-all cost. To use ON-OFF
control, set PB to zero and O1HY at 0.1°C.
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