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.....
The basics of control system design
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
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.
Connect Sensor properly and replace when broken
keep sensor close to the source of cooling.
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.
and Automation - 02
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. (hermetically
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
Temperature Control with PID and SSR
RTD Sensors to Terminal Block
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.