How to control furnace temps? Ramp and Soak in labview?

[Gerry S]

Please help me~~~~

I use Labview version 8.2 and Compact Field Point.  I currently have a small Lindberg/Blue furnace (120V, 6.8A, 8KW) that has a mounted Lindberg/Blue UP150 programmable controller.  The temperature control is not currently connected to my PC (and that's a pain). 

I would like to replace the present furnace controller with labview control through Compact Field Point.  I need to create a ramp and soak program in labview.  My

program must be able to:

Soak at 300C for 30 min

ramp to 650C

soak at 650C for 15 min

ramp to 700C

soak at 700C for 10 min

cool to 300C

repeat the above steps as many times as desired.   

I am familar with labview but have never controlled any furnace temps.  I have figured out that I will need the PID control toolkit.  But I'm totally stumped about the hardware I will need.  I have searched everywhere but can't find an explanation.  I have Compact Field Point and the furnace.  What hardware goes inbetween?  Just what hardware does the PID toolkit (PID VI's) send a signal to?  It seems to me the PID would read a thermocouple and then send a signal to some sort of current regulator that sends a varying current to the furnace.  Am I way off?  How do I set this up.  Can anyone recommend a good book or web site that explains how to set up furnace control using labview?   

I really appreciate your help.  I'm at the end of my road without it.  Thanks alot. 

-Gerry

[Khalid]

Hello Gerry,

How is the heat in the furnace controlled currently?  Is it by regulating the current to it?  If yes, then you could use an Analog Output (Current) module.  The PID's output would then be written to a channel on this module to output the right amount of the current.  This way you will achieve the right temperature.

Obviously you will need a Thermocouple module to read the temperature in as well (assuming you have thermocouples as the sensors).

Hope this gives you some ideas.

-Khalid

[Gerry S]

The furnace is currently controlled using a UP150 temperature controller from Linberg/Blue.  I'm not sure how that controls the temperature, whether it's through a variable current or if it's through a pulse width modulator method.  I will be using a CFP-TC-120 board to read one type K thermocouple for the input to the PID. 

Thank you very much for helping so far!