PCI6229 THERMOCOUPLE AD595

[128]

Dear friends,

I am new in using thermocouple. All hardwares I have is PCI6229 and K type thermocouple with amplifier AD595. I am using Labview 8.0.

All I want is using those things to make some simple measurement, for example room temperature. However, I don't have any clue where should I begin. I am trying to connect AD595 properly.

Hope anyone can give me some advice.

Many Thanks

probiee

[K_Bull]

Hi there probiee,
You can find the pin layout of the PCI-6229 in the data sheet (page 22). You can also find the data sheet for the AD595 here. This has previously been discussed in this post.
I hope these links help you with the connection. If you are using Labview to acquire, there should be shipped examples to help you. To see if you are acquiring the signals or not, you could use the Measurement and Automation eXplorer (MAX).
Best Regards,

[jriley]

Probiee,

To simplify operation of the AD595 chip use only a single operating voltage of +15VDC for Vcc. Using +15VDC will give you a larger operating range than +5VDC for positive temperatures from ambient Deg. C to +300 Deg. C. There is no need to use dual voltages unless you aer temperature cycling from a sub zero temperature to and extremely high temperature. If you are using shielded thermocouple cable do not ground the shielding because it load the AI Channel with excess noise of up to two volts on the input pin to the AD595. You will find it it better to float the ground on the shielding of the thermocouple cable to eliminate the excess noise. Also when soldering the thermocouple wires to the inputs of the AD595 will require a specific type of solder other than is commonly used for soldering. (Reference any of the three Analog Devices application notes for the solder contents.) Per NI's M-Series User's Manual states that a biasing resistor should be connected from the negative terminal to AI GND for a differential connection such as used for thermocouples. In my experience a resistor of 2.7k Ohms will work the best to eliminate noise. Also I have tried put different coupling capacitor between AI plus and negative terminals for a channel with no results in getting rid of the noise. The only thing that the different capacitance values caused was loading down the AI channel.

Good Luck, JR