Help PT100 sensor - Electronic Circuits Projects Diagrams Free

Algerian · 30th June 2007, 10:15 AM

Hello,
I want to get temperature readings with pt100 sensor, does any one have a circuit to connect it to pic16f877, thanks in advance

j.p.bill · 30th June 2007, 03:58 PM

If that is a platinum RTD, you will need to send a currrent through it from a controlles source. Using a high-quality amplifier, amplify the voltage on the RTD up to a level compatible with the A to D converter in the PIC. After conversion, apply the values against a look-up table to linearize the signal.

One observation, though - an RTD is a very expensive and precise measurement device. Reading it with an 8 or 10 bit A to D is a bit like measuring dimensions in ells and spans. The units are just too coarse to give good results.

Algerian · 30th June 2007, 04:14 PM

Quote:

Originally Posted by j.p.bill

If that is a platinum RTD, you will need to send a currrent through it from a controlles source. Using a high-quality amplifier, amplify the voltage on the RTD up to a level compatible with the A to D converter in the PIC. After conversion, apply the values against a look-up table to linearize the signal.

One observation, though - an RTD is a very expensive and precise measurement device. Reading it with an 8 or 10 bit A to D is a bit like measuring dimensions in ells and spans. The units are just too coarse to give good results.

Thank you very much for your reply, but please, if you have a reference of the high quality amplifier, or if you have the circuit with refernces and values will be very helpfull. Thanks again.

RadioRon · 30th June 2007, 08:07 PM

If you are in a hurry, just buy one of these:
http://www.omega.com/ppt/pptsc.asp?r...94A&Nav=temn03

If you want to build from scratch, Maxim has some chips specific to this application:

http://www.maxim-ic.com/products/sen...rmocouples.cfm

and here is a useful application note with IC references:
http://pdfserv.maxim-ic.com/en/an/AN3450.pdf

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30th June 2007, 10:15 AM	#1
Algerian	Help PT100 sensor Hello, I want to get temperature readings with pt100 sensor, does any one have a circuit to connect it to pic16f877, thanks in advance

30th June 2007, 03:58 PM	#2
j.p.bill	If that is a platinum RTD, you will need to send a currrent through it from a controlles source. Using a high-quality amplifier, amplify the voltage on the RTD up to a level compatible with the A to D converter in the PIC. After conversion, apply the values against a look-up table to linearize the signal. One observation, though - an RTD is a very expensive and precise measurement device. Reading it with an 8 or 10 bit A to D is a bit like measuring dimensions in ells and spans. The units are just too coarse to give good results.

30th June 2007, 08:07 PM	#4
RadioRon	If you are in a hurry, just buy one of these: http://www.omega.com/ppt/pptsc.asp?r...94A&Nav=temn03 If you want to build from scratch, Maxim has some chips specific to this application: http://www.maxim-ic.com/products/sen...rmocouples.cfm and here is a useful application note with IC references: http://pdfserv.maxim-ic.com/en/an/AN3450.pdf __________________ RadioRon Last edited by RadioRon; 30th June 2007 at 08:10 PM.