temperature controling

[hsadegh]

Hi  I wana control my temperature in a system so to an optional curve(sinusoidal, cosine wane, etc), how can I do that,does It needs programming? I have some primitive data like my momentary temperature, how can I match my temperature with my desired curve that gives me an acceptable precision.

I work with ni-usb 6009

[Gregory]

Hello hsadegh,

Yes, you will need to write a program for your application. How are you controlling the temperature? Do you output a voltage that controls a heater/cooler? Usually temperature control devices like a TEC require a current draw that I'm not sure the USB-6009 is capable of.

Assuming you do have a way to control the temperature through either a voltage or current, it will probably not be enough to simply send a sine wave of voltage and hope to get a sine wave in temperature. Most people use a PID loop to get as little overshoot as possible, but you may be able to purposely create an overshoot by raising the D parameter. Then you can change the rate of your update loop to adjust the frequency of the ringing a little bit. I don't know if this will be as precise as you want though, but it will probably be an exercise in trial and error.

[hsadegh]

hello  gregoryj

I almost understand what you said, I used the voltage(LM35 sensor) to check my realtime temperature, I used PID control to regulate my temperature but I don`t know how to define and control temperature in a sine wave like diagram.

[Minions]

How do you communicate with your temperature chamber?  Is it through GPIB? Ethernet/LXI? Serial? other???  What chamber are you using for temperature?  What instrument(s) are you using to read back the temperature from the chamber and how are they being controlled?