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Anonymous Poster

Thermocouple

07/21/2009 10:32 AM

can anboby pls tell me how to measure thermocouple with multimeter,while i was selecting temperature display on the multimeter, my input was 150c and i got 150 on the display but when i checked with reference to the temperature chart (mv) mv volt started showing less, chart and mutimeter is not matching

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#1

Re: Thermocouple

07/21/2009 10:44 AM

If your multimeter is designed to display temperature when connected to a thermocouple, it will incorporate circuitry to perform cold junction compensation (click to read about it in wikipedia).

Measuring the thermocouple voltage with a multimeter and using a lookup table to find the temperature will not give an accurate result.

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Anonymous Poster
#2
In reply to #1

Re: Thermocouple

07/22/2009 12:08 AM

Thank you john

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#3

Re: Thermocouple

07/22/2009 12:24 AM

Depending on the CJ temperature of the meter, you may be introducing errors by using a meter in temp mode.

Make sure the meter CJ temp has equalised with the ambient temp before taking a reading.

The most accurate method is to only measure mV, and measure the CJ temp accurately (hi resolution laboratory glass thermometer, or RTD in a CJ box), then use your tables.

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#4

Re: Thermocouple

07/23/2009 12:35 AM

You check millivolts from Thermocouple and than check on table where is temperature against millivolts

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#5

Re: Thermocouple

07/23/2009 12:42 AM

if both mv against chart and temperature displaying on multimeter r same than thermocouple giving prob. if differ in reading on multimeter than change multimeter, by ranjha

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