Hi guys, thank you for your reply.

I'm sorry I didn't get back to you quicker... I did write a reply a couple of days ago.. when I hit the send button it asked me to log in. When I did... something messed up and I lost the message I was going to send. Bother.

So this will be a quick one.

The ribbon is stainless steel, .005 inches thick by 3/4" wide by 17" long. I did the math at work and the resistance at room temperature is something less than one ohm. (.34?) I don't remember. Sigh**

The ribbon is mashed between two parallel bars with silicone and mica and a few other materials in between. I want to pulse the ribbon with enough current to get it up to about 700 degrees F in 10 seconds or less. Then hold it there for a few dwell seconds, and then turn off the power and allow it to cool back to 150 degrees F.

Of course I want to control this sealer for all other temperatures as well. The typical maximum is 700 degrees F. Fluropolymers such as Teflon FEP, PFA and Modified PTFE seal between 550 and 650 degrees F.

The sealer I built currently has a Dallas thermocouple device that reads a thermocouple input and interpolates it. The pic polls the device and retrieves temperature serially every 21(?) seconds or so. This is pretty good but not nearly as fast as reading the ADC channel directly. So if I could tap in to that speed, I could more precisely control current and thus temperature.

I know this can be done because it is being done in a Ropex controller. I believe they are using a current sensor to measure the current during an on cycle. They are also either reading the voltage drop across the bar during an on cycle or the resistance inbetween cycles.

Well I have to run for now.

Thank you for your feedback! Any other comments, criticisims, wise cracks or suggestions are eagerly sought!

Ross