Thermocouple

I have a Horner Thermocouple Input Module.
How do I write a program to control the temperature.
I have a GE 90-30

Not enough info mate.

Give us as much as you can, including what you've done (programs, pictures, ideas, outcomes), hardware involved, what process you're controlling, accuracy required, thresholds.

The more you help us the less reluctant we will be to help you.

Normal you should use a PID, but as mentioned before, you give a very little information.
Most inportant, what is bandwidth between the lowest and highest temperature which your process need?
How many zones do you like to control?
Do you realy like to program a temperature control by your self?
Have you ever looked at the Omron Celciux? We use these units here in the factory to control nearly all our heaters.