Temperature Controller Applications
Cooling Chamber Temperature Control
The Logic of cooling in temperature control is inverted, Activating the
relay
powers a compressor which cools the system. A small modification at the
output stage, makes any heating controller into a cooling controller.
It can also be done with external relay logic, but make sure on power
failure (control power line) the compressor ( 3 ph power) shuts down.
In all heating and
cooling control, when a broken or disconnected sensor is detected, the
controller should turn off all outputs and indicate a fault condition.
Before you use a Controller to Cool a Chamber to Say +5
Deg C.....
First :
Do not Connect the Controller. Directly Connect the
Cooling Device e. g. : Compressor. to the system and check the maximum
cooling it can produce. In case temperature goes to 0 deg or -10 deg
then by using a STC1000 you can control at +5 deg.
But if directly you get cooling of only upto +10 deg
then it is impossible for any controller to produce extra cooling, in
such a case as this use a better compressor or more insulation.
Second :
Connect Sensor properly and replace when broken keep
sensor close to the source of cooling.

Third :
Deadband (DB) at minimum is 1 Deg this is the best
setting, maximum setting of deadband may increase compressor life and
also save power but will produce a huge variation in temperature.
Fourth :
If large Variation of temperature is present and you
need accurate control Reduce deadband to min.
Unit is factory set db at 1 deg, remove seal tape
before dead band adjustment.
Capacitor Temperature Monitor With STC3000
When placing sensors in high pressure or vacuum chamber, they should be
terminated by an epoxy sealed terminal block interface on the system. 4
wire RTD is best for such applications, as multiple
terminations and junctions are involved; also the wires may have to run
some distance.
When measuring temperature in a big surface or object, use multiple
sensors. An indicating scanner-controller can be used or ensure
cooling-heating is
uniform using fluids or air circulation.
RTD Sensors to Terminal Block Connections
W - is White Wire from RTD, R - is Red Wire from RTD, Color of Wire on
RTD Sensor Pt-100.
Top 3 Terminals are for RTD 1 (Red), Bottom 3 Terms. are for RTD 2
(Yel), Marked with Color Tape.
The RTD two whites go to one end of the Platinum 100 ohms resistive
sensor, the red goes to other end. The red in this sensor goes to
gnd of opamp circuit in controller. Thru one white a 1mA current is
injected, the other white gives a voltage output to opamp. This voltage
after offset and calibration is proportional to temperature.
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