RTD interface circuit

[BABESH]

rtd circuit

I have Pt-100
I need circuit whose resolution is 1mv change for 0.1 Degree C change.

Presently i am working with ckt whose resolution is 0.03mV for 0.1 DegreeC,
But i don't want to operate in that region.

Any circuits of such kind?

tks

 

[IanP]

rtd interface

Take a look at the attached picture ..
If you need 1mV per 0.1° output change 49.99kΩ resistor to ≈250kΩ - this will set the gain to 26 - and the output of this amplifier will produce 1mV for every 0.1° ..

Regards,
IanP

 

[BABESH]

rtd interface circuit

hello ianP
tks for ckt,
but i have a doubt about internal offset of op-amp,
will this ckt have this compensation?
any way i will try this on bread board.

Tks
--babesh

 

[haytham]

circuit rtd

Hi
I was facing the same problem few months ago.
I got a circuit which will give 20 mv for 0.1 C change. It was consisting of IA, OPmp and Active LPF.

I can't email it to u. but I could help u in imlemting your own

Added after 6 minutes:

IA : instrumentation amplifier
Opamp was used to adjust offset and final gain adjust.
Active LPF : was to eleminate supply noise due to Full/half wave rectifier.

Also there were current sourse that was used to fed the sensor with refrence current

 

[vipul]

interface circuit

Hi Babesh..
Did u get the output from above ckt????
I tried ckt on bread board as well as with simulation but it doesn`t work...

If you have any circuit for PT100 interfacing..can u post it here????

Thanks...

 

[BABESH]

current source circuits for rtd

Hi vipul,
I did this without using current source.

My circuit is just one non-inverting configuration.
with +Ve fed with 500mV Vref, Rf=100Ohms,
R1=pT100.
It worked fine....



Thanks
Babesh.

 

[vipul]

interfacing to 1mv pic

Hi Babesh,

Thanks for reply...

Actually I also get output of circuit with some changes...

Thanks,
Vipul

 

[mitulshinde]

rtd interface circuit

Hello,

Can you give me circuit idea that convert 0.1 centigrade to 10 mV?

Reply me Soon

Regards,

Mitul Shinde