Thermocouple playback

Have you looked at Omega? They have a variety of thermocouple data loggers.

http://www.omega.com/ppt/pptsc.asp?ref=OM-CP-QUADTEMP

Hi

what type of thermocouple you are using.

what is your budget.

There are many solutions available to solve it.

Now a Days PC based systems are in use to build application like this.

so please specify in datails along with your budget.

Thanks.

I talked to the a temperature sales engineer at Omega and they did not have a solution with a fast enough response. I also got information from their DAQ department . The DAQ solution is the same as the NI solution.

That is, take a DAQ boaard with analog output, and with software record and play back. I have an NI board and an IOTech board that can do this and I am fairly familiar with LabVIEW. With a resistor divider I think I can do this.

I was looking for a more portable, standalone solution. No PC required.

We also have a TEAC RD-125T DAT recorder that has been sitting around a while. No manual and no tapes. Not sure if it works. I checked with TEAC and the new version of this cost $15K.

I would like to record at least S type TC (R, K B would also be nice) one one channel, the a mV signal up to 400mV on a second channel.

I actually would like two of these setups, but once I get one I can just duplicate it, but a system will all 4 would be nice.

Budget wise, if I could stay under $1000 we would be happy.

This does not have to be calibrated or high accuracy...It is just for testing a new DAQ system we are developing to see how it reacts to difference temperature profiles. It will save us a trip to the field.

How about a scopemeter? You can get them for few $100, they have digital storage and the response time you need. You can download the measurement to a PC. They're small, portable and battery powered.

There are several data loggers that are available that can handle that job. Honey Well, Thermo Electric, Omega, Yokagawa and others.

The Type S (platinum/platinum-rhodium) thermocouples are not linear so if you use an of the shelve logger, you have to have a program to change the millivolts to degrees C/F.

To get a good profile of the temperature changes of a thermocouple going from ambient to 1600°C in one second, you would need a fast DL.

I have experience using the Eurotherm 5000B data acquisition unit. The fastest sample rate I have run at is 1 per 0.25 second for a 24 hour period but I think they can sample faster for a short duration. Output is diplayed on a PC screen with software supplied.

Contact www.eurotherm.co.uk

The hard part here for me is the playback function.

I need to record a thermocouples mV signal and play it back exactly in analog.

I do not even need to look at it or analyze it. Just play it back with the same timing and 1 to 1 ratio for the amplitude...I don't even have to know it is a thermocouple, just save it as a mV trace.

There has to be a cheap way to save and play back analog signal of the mV or microvolt range.

Can I use something like a tape recorder...MP3 player?

I read that PC sound cards are DC coupled, and there is low frequency filtering so anything under 20 Hz is filtered out, so this would not work.

Here is the NI solution. http://zone.ni.com/devzone/cda/tut/p/id/4310

I will play around with it today.

Best Regards,

Carlos

Hi

I want to add one more doubt in this topics, How much (minimum) samples you want to read or write to a file. You want any FFT annalysis. There are somany PC based or Distributed I/0 (for real time) are available. Dont Go for NI - Compact RIO. In NI PCI, PXI, SCXI, and Field points are much cheaper and easy to control than Compact RIO.

If you want to talk to me means my number is +919894465503 (india).

K.P.Mahalingam

Electrical engineer.

India (south).

And in this time how many readings do you need? I believe that you will need a data logger that is very fast, reads in the millivolt range, and since you want it in analog, a D&A converter.

Maybe a oscilloscope set to take a one sec reading?

If you can manage using a laptop, iotech's personal daq 3000 would work nicely. it has wave form playback capabilities and 1MHz sampling rate. if not, i use a edirol audio recorder for S&V field data acquisition with playback... i only use it for sound measurement though, not sure if it will serve your purpose.

Hello,

I agree with what was said before, as there are a lot of companies selling the equipment you need, but let me add one point.

You say "16 bit resolution .. is necessary". As an electronic developer I have built a lot of DC-precision equipment (for thermocouple, too) - but, believe me, everyone telling you that you get 16 bits of STABLE and USABLE resolution lies. And everyone who WANTS 16 bits of usable thermocouple resolution does not know what it takes to realize that or possibly does not know what he really needs (sorry, I dont want to compromize you and dont know your budget and real requirement).
Imagine that to get 16 real (=DC-stable and reliable) bits you have to thermo-control your instruments within very small differences, you have to avoid air-movements around your Opamps inside the device, the whole unit has to be built with special thermo-voltage free solder and so on.

1600°C divided by a resolution of 16 bit is ~0.025°C - do you really need that or would it be ok for you to have a USABLE resolution of ~0.4°C which you have with 12 bits ?

Remenber that increasing the coherence between reliability and costs is not linear but exponential.

Hope that helps overthinking
Uwe