Sensor Input Conditioning

Oct 13, 2005 3 Replies

Rate this thread:

Richard 20 years ago

I have to build a terminal board which will accept

0-5 vdc
1-5 vdc
0-20 ma
4-20 ma RTD

all jumper selectable. Each channel will have 3 terminals, Grd, 12 vdc, and Signal. The ADC input is for 0-5 volts. I have all the voltages and milliamp ranges figured out with jumpering a 250 ohm precision resistor to ground for milliamp.

How does one convert a RTD signal to voltage? I've tried to search but I'm coming up with more sales then tech info.

Thanks, Richard

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----

formatting link

The #1 Newsgroup Service in the World! 120,000+ Newsgroups

----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Vote

PeteS 20 years ago

You can read about RTDs at:

formatting link

Cheers

PeteS

Vote

Jamie 20 years ago

Newsgroups

RTD's are resister devices. you have a set ohm value at a set temp. it simply is a resister changing it's value with temp.. off the top of my head i can think of one that is 100 Ohms in spec. many devices use a current limiting source in series with a calibration with a RTD to supply a 4..20 ma current input.

Real Programmers Do things like this. http://webpages.charter.net/jamie_5

Vote

Jasen Betts 20 years ago

feed it with a constant (or predictable) current and measure the voltage across it. use a small current to avoid heating the device.

a large resistor to +12V would be a good start.

Bye. Jasen

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required