GO POUND GROUND ...

ABOUT TEMPERATURE CONTROLLERS

AND TEST LOADS

Setting up a test load and testing with a temperature

controller allows you to test the direction of current flow

though the load. It shows the polarity of the controller and

whether the sensor feedback is working properly.

The following equipment is necessary when setting up a

test load:

•

Thermoelectric controller

•

2 Multimeters, one set for voltage and one for current

•

5 V Power supply

•

Connection cables or wires

R1

SEN-

SEN+

Figure 4. Thermistor Test Load

RLOAD

TEC+

TEC-

RLOAD

IMETER

Figure 5. Simulated Thermoelectric Test Load

SET UP THE TEMPERATURE CONTROLLER

TEST LOAD

1. Attach a 10 kΩ resistor in place of the thermistor (see

Figure 4

) with a default sensor bias current of 100 μA.

The ACT T voltage should read 1 V when the controller

has power applied.

2. Connect an ammeter in series with the test load resistor

(see Figure 5).

NOTE:

The positive terminal of the meter must attach

to the TEC+ output of the controller and the negative

terminal of the meter must attach to the test load resistor.

Make sure the ammeter capacity exceeds 1 A.

3. Attach the voltmeter across ACT T and GND.

4. Attach a 5 V power supply to the unit. A higher voltage

power supply can overheat the controller when using

test loads.

5. Turn limit trimpots to OFF (usually 12 turns CCW).

6. Enable the unit.

7. Turn the SET T voltage to 1.35 V for cooling and turn

the Current Limit trimpot until the ammeter reads 1 A.

The limit setting can be any value as long as it does not

exceed the ammeter capacity or the power rating of the

load resistor.

8. Turn the SET T voltage to 0.8 V for heating and turn

the Current Limit trimpot until the ammeter reads 1 A.

The limit setting can be any value as long as it does not

exceed the ammeter capacity or the power rating of the

load resistor.

9. When the testing is complete, return the Current Limit

trimpot to the OFF position (usually 12 turns CCW).

CONCLUSION

Once you are comfortable with using the equipment, then

it can be powered down and the test load removed. Make

sure everything is reset, such as returning the Setpoint

trimpot and the Current Limit trimpot to OFF (usually 12

turns CCW) before connecting the application load. Once

the actual load is connected, start the set up protocol from

the beginning. Be sure to use the appropriate datasheet

when setting up the application load.

Using a test load to become familiar with your Wavelength

product will help protect your application when setting up

the final load. As always, our technical sales engineers are

available to help with any questions you may have.

© 2014 • Sales & Technical Support: (406) 587-4910 • email: Sales@teamWavelength.com • web: www.teamWavelength.com

Application Note AN-LDTC04 Rev. A

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