PIC + type K

[trexter711]

Hello everyone. I'm just wondering if I can use a type K thernocoupler direct with any PIC.

Thanks

 

[Nigel Goodwin]

Almost certainly not, you need to amplify the output a LOT to make it large enough.

 

[aljamri]

sinc k-type has a range of (-200 °C to +1200 °C) as per: https://www.picotech.com/applications/thermocouple.htm
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you may use PT-100 if its range is suitable ( -200°C to +850°C ) see :
**broken link removed**.

 

[Sceadwian]

If you want quick and dirty, a simple opamp to amplify the signal will work enough to give a PIC's ADC something to work with. But you better be a damn good programmer and signal analyst to make any degee of precision from it.

 

[trexter711]

Thank you for your fast reply. I read somewhere (I don't recall...) that there's a pic that can handle type k thermocouple. I searched on "www.microchip.com" but nothing there about this subject. Anyone knows about it?

 

[Eclipsed]

The MAX6675 is probably the easiest/most accurate way of using a K type with a microcontroller.

**broken link removed**

 

[mvs sarma]

Hello everyone. I'm just wondering if I can use a type K thernocoupler direct with any PIC.

Thanks

i an posting a PIC design document of temp sensors. on page 10 you find k-type thermocouple.

 

[aljamri]

Great document

i an posting a PIC design document of temp sensors. on page 10 you find k-type thermocouple.

Thats a great document, whats the adress to get simillar document for another sensors.

Thanks

 

[mvs sarma]

It is downloaded from www.microchip.com directly

 

[Oznog]

There are ADCs like the LTC2418 that handle thermocouples fine.

A normal op-amp won't work well no matter how good a programmer you are!
The problem is offset, thermocouple inputs are so small that common opamp offsets might make hundred of degrees F of error.

Second thing here- is this thermocouple grounded? It's ok to do that, not only we can bolt both wires to a grounded cylinder head, in fact a thermocouple can even measure a temp on a grounded hot plate by bonding one wire at one point and the other wire at a different point! But this means one voltage is slightly above ground, the other slightly below, so we need to be able to measure slightly below ground AND we need to be differential.