Thermocouple conversion.

[Double V]

Hi all

Has any one got an idea on how i can convert a thermocouple to a pt1000 equivalent signal

The grape industry in SA insists on a thermocouple left in the middle of the pallet as this is the most inexpensive measuring device that can be left in. I need to monitor & measure this temp but most monitoring systems will only measure pt1000 or pt 100 probes.

Can it be done?

[STS]

A thermocouple gives a milivolt signal. A Pt100 or Pt1000 gives a resistance signal. I have never heard of a signal conditioner that will convert thermocouple to Pt100. Your best bet is to look into what process signals your monitoring equipment can accept and then add a signal conditioner between the thermocouple and your equipment to convert the milivolt thermocouple signal to something useable like 4-20mA or 0 to 10 volt

[The MG Pony]

Hmm a transister? it sets the intensity of the signal vers the base input so its resistance goes up as base goes down.

[star882]

What about a second thermocouple in a metal block attached to a side of a small Peltier, wired such that the total voltage would be zero if the temperatures are equal. An opamp senses the voltage and heats and cools the block using the Peltier to try to make the temperatures equal. Then put any kind of temperature sensor you want in the metal block, keeping it close to the reference sensor as possible.

[Andy]

Hi all

Has any one got an idea on how i can convert a thermocouple to a pt1000 equivalent signal

The grape industry in SA insists on a thermocouple left in the middle of the pallet as this is the most inexpensive measuring device that can be left in. I need to monitor & measure this temp but most monitoring systems will only measure pt1000 or pt 100 probes.

Can it be done?

Hi Double V:)

Conversion cards are available for PLC applications between thermocouple and PT100.:)

Siemens PLC's have these.
I will look for a link.

Kind Regards Andy:)

[easttn]

I think what you need is a Thermocouple Temperature Transducer. There are many manufacturers, google it.

[Larry2]

If you're allows to solve the problem rather than accept the solution they picked, consider one of the temperature sensor intergrated circuits. They are pretty accurate and cheap. They are linear, providing 10 mv delta per degree F. You can connect any number of analog data capture devices to this, including analog to digital converter i/o cards for PC's. One such device is the LM34. There are newer ones that communicate through serial data lines. Here's a data sheet for the part. I like this component very much. Heck of a part for under a buck.

http://www.national.com/pf/LM/LM34.html

[Peter_1]

I think what you need is a Thermocouple Temperature Transducer. There are many manufacturers, google it.

Al this convert the TC to a mA or a mV or a V signal. He needs TC to PT100 or PT1000.
Impossible and especially if it should excist, it will be expensive, just the opposite as what his client wants.
You need as others say a converter to a signal your monitoring systems accepts.