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How to avoid the occurrence of sensor errors for air conditioning system? 2016-08-11


The temperature sensor that NEWBASE controller should work with, is NTC sensor, that means  Negative Temperature Coefficient thermosensitive resistor type. The resistance value vary with temperature and send the single to aircon control unit.

To avoid the error of temperature sensor, we should know well about the reason leading to sensor error so that to use the sensors best.

Generally, there are several reasons as below cause sensor error.

1. The mounting position of sensor. The mounting area should not be close to doors or heating area, the insertion depth is 8 to 10 times of protection hose diameter. The sensor cables should not be in same hose with power cable to avoid error due to disturbing.

2. The insulation. If the thermocouple is insulated, or too much sundries in the protection hose, that would lead to poor insulation, it would be even more serious under high temperature. It not only waste thermoelectric force but also bring in disturbing, the caused error could be more than 10 degree C.

3. Thermal resistance error. If there is dust on the protection pipe, increasing the thermal resistance value, and hinder the thermal conduction, then the detection temp value is lower than real temp. So, we should keep the sensor probe clean.

4. Error caused by thermal inertia. The show value is delayed than exact temp change due to the thermal inertia of thermocouple, this situation would be heavier for fast measurement. So we should choose thermocouple with thinner thermode and smaller diameter of protection hose as far as possible. The protection hose even could be removed if the temp measurement environment allowed.

Usually, user would throw doubt upon the products with above error. But in fact, the error is caused by improper operation somewhile. In this case, pls check the sensor situation and installation method firstly.

For checking the variable value of resistance value of Newbase sensor with temperature,please refer to following table(part).

R25=5KΩ + 1%, B25/50 = 3274.1K  + 1%, indexing 127


T(℃)

R↓(%)

Rmin(KΩ)

Rcrit(KΩ)

Rmax(KΩ)

R↑(%)

-40

-3.972

97.7821

101.8267

105.9571

4.056

-20

-2.855

31.5134

32.4393

33.3754

2.885

-10

-2.402

19.9878

20.4797

20.975

2.418

0

-1.974

13.0275

13.2899

13.5532

1.981

10

-1.567

8.6847

8.8229

8.9614

1.569

25

-1

4.95

5

5.05

1

40

-1.523

2.914

2.959

3.0042

1.527

60

-2.152

1.5333

1.567

1.601

2.168

86

-2.875

0.7304

0.752

0.7739

2.915

 

Should you have any query during use newbase controller sensor, don’t hesitate to let us know.