how to connect AD595 thermocouple amplifier?

[Sama]

Dear Jex

I am connecting Type K thermo couple to the AD595AD and I also have the 6008 Card, so my case is similar to yours, first i used to get the 5.5mV output, and i relialized that my mistake is not grounding pin 1 , so pin number on ehave to be connected to the (com (4) also (7) )

so if you connect your thermocouple to 1 & 14 and ur 5 V input to pin 11 and the the ground of input to ( 1, 13, 7 , 4 ) things will go fine, how ever the multimeter will seem so stable but the signal is too noisy ! strange I have terrible noise and when I get the arithmetic mean of the signal using the labview I get progressive error starting from 1 Degree till 4 degrees.

If I am too confusing I'll send you a drawing, and kindly tell me ur opinion In the noise since I'm a mechanical engineer after all.

thanks

[Sama]

Dear jex,

take a look at this attachment please and tell me ur opinion.

which is which in the thermocouple itself ,simply tiral one will work and the other wont 🙂

I need help on noise ( the computer started reading better values when i did put 100 ohm resistance in parallel with the signal ! strange!

thanks

[justinvt]

Has anyone ever successfully blown or otherwise broken an AD595?  I have gone from getting continually bad readings to getting a constant output of 0mV now, and I'm wondering if some aspect of my setup (cheap breadboard, power supply...) has gone bad, or if I have ruined the chip itself.  My multimeter is fine, and the thermocouple itself is definitely producing the proper output.  Is any way to determine for sure if the chip is working/not working?  Thanks in advance.

[LabViewGuruWannabe]

justinvt, I'm sure lots of people have fried these chips. They are senstive to ESD and miswiring, just like every other integrated circuit. However, these are pretty rugged. Make sure your input voltage is stable, that all of your grounding wires are in place, and if worse comes to worse, simply replace the chip with another one. It looks like they're not available from Analog Devices at the moment, but Digikey has them in stock.

Sama, how much noise are you seeing with your setup? Do you only see noise coming from the TC amp, and not with any other analog signals? With my 12-bit input device and the same basic circuit talked about here, I get some noise, but its in the +/- .005V range, or roughly +/- 0.5ºC range. And that's without using twisted pair or shielded wiring. Since I don't need better than +/- 5 degrees, that level of noise is acceptable.

Good luck!

B-)

[jex]

have u check the pin of the connection propely, the pin number 1 should be grounded then u will see the effect, and i can suggest u done in a pcb board, whereby u can buy a ic soket and then jz place the thermocouple on it, it should give u a perfect work, u can refer the schmetic diagram from a few repling thread, i based on the schemetic diagram fix it, it works well

Message Edited by jex on 08-08-2007 07:45 AM

[Sama]

Dear All,

Concerning the noise After trying several sampling rates the accuracy is better far more better , the actual problem in in the selection of the K-type since my range of measurement is from room temp, till 100 C , so .5 C really matters, its a lab. educational stand...

I attached here a part of the signal conditioning unit showing the connection of the AD595AD with breadboard wires and input and output managed to be on one side and clear.

I am really interested and learning from reading in this thread.

thanks

[ighkou]

Hi ,
I am making a data acqusation system with 20 K type thermocouples.my connection are are thmermocouple>maleconnector>female cooncteyor>sheldedwire of 15-20 cm >wire end soldered on pcb>muxdg407>ad595cq>muxDG406>adc ad574>89C52>pc .
I have got the prolem of fluctions.when only one thermocouple is connected i get small data varation of 2-3 oC but if 2 thermocouples are connected the tmep get out of control to 200 to 500 .even at room temp.also when i put my thermocouple in hot water.
I have earth the the body of thermocouple and grounded pin-1 of ad595.if i donot ground it my output goes to zero even if thermocouple body is earthed.
plz if any one can suggest a solution. or tell me what and where the probem is.Thanks

[ighkou]

Hi ,
I am making a data acqusation system with 20 K type thermocouples.my connection are are thmermocouple>maleconnector>female cooncteyor>sheldedwire of 15-20 cm >wire end soldered on pcb>muxdg407>ad595cq>muxDG406>adc ad574>89C52>pc .
I have got the prolem of fluctions.when only one thermocouple is connected i get small data varation of 2-3 oC but if 2 thermocouples are connected the tmep get out of control to 200 to 500 .even at room temp.also when i put my thermocouple in hot water.
I have earth the the body of thermocouple and grounded pin-1 of ad595.if i donot ground it my output goes to zero even if thermocouple body is earthed.
plz if any one can suggest a solution. or tell me what and where the probem is.Thanks

[Wallace10]

Hello All,

              I'm new on the site and kindly assit me on how to acquire temperature data from Type K Thermocouple (0 to +50 degC) using AD 595 t/c amplifier and NI USB6008 DAQ module. I will appreciate any similar Labview VI that can aid my understanding of the DAQ.

[Coq_Rouge]

Hi it is always better to start a new thread instead of "hijacking" older threads. Hijacking in most forum is not allowed. So I strongly suggest you start a new thread. Then you post a link to your new thread in this thread. Then you have done this I will help you.