how to make the temperature reading response faster??

[haowhaow]

im using thermocouple type k and display the reading at lcd.....
but i found that my reading display need to take time to reach the measuring temperature..

how can i make it response faster and more precises?

 

[hotwaterwizard]

An Analog Meter goes faster.

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[Reloadron]

im using thermocouple type k and display the reading at lcd.....
but i found that my reading display need to take time to reach the measuring temperature..

how can i make it response faster and more precises?

You really aren't providing any information beyond Type K thermocouple. What type of Type K (if that makes sense) as in open junction or closed? Sheath or non-sheath? The wire gauge of the TC wire? How are you sampling the mV outfrom the junction? What is the sample rate? If using A/D conversion, how many bits? What range of temperatures using type K are you measuring?

You really need to define the application is some detail and the thermocouple in some detail to get a good answer to your question.

<EDIT>

As to thermocouple response time(s):

What is response time?

A time constant has been defined as the time required by a sensor to reach 63.2% of a step change in temperature under a specified set of conditions. Five time constants are required for the sensor to stabilize at 600 of the step change value. Exposed junction thermocouples are the fastest responding. Also, the smaller the probe sheath diameter, the faster the response, but the maximum temperature may be lower. Be aware, however, that sometimes the probe sheath cannot withstand the full temperature range of the thermocouple type.

You may want to give this a read. It covers a few of the considerations when selecting and using thermocouples.

</EDIT>

Ron

 

[haowhaow]

You really aren't providing any information beyond Type K thermocouple. What type of Type K (if that makes sense) as in open junction or closed? Sheath or non-sheath? The wire gauge of the TC wire? How are you sampling the mV outfrom the junction? What is the sample rate? If using A/D conversion, how many bits? What range of temperatures using type K are you measuring?

You really need to define the application is some detail and the thermocouple in some detail to get a good answer to your question.

<EDIT>

As to thermocouple response time(s):



You may want to give this a read. It covers a few of the considerations when selecting and using thermocouples.

</EDIT>

Ron

oh....thankz alot....i will read it.....

 

[binzer]

im using thermocouple type k and display the reading at lcd.....
but i found that my reading display need to take time to reach the measuring temperature..
how can i make it response faster and more precises?

How often do you scan and convert the info? (response time)
How many bits is the adc you are using? (precision)

 

[haowhaow]

How often do you scan and convert the info? (response time)
How many bits is the adc you are using? (precision)

im using PIC18f4520 which have 10bit.

 

[Reloadron]

im using PIC18f4520 which have 10bit.

How are you conditioning the thermocouple output. You can't just run a thermocouple into a PIC. You have the thermocouple, you have the PIC and what do you have between the thermocouple and the PIC?

Ron