Comparative Vacuum Valve Controller

Hi All,

First time here and my first experience with Arduino. I have a vacuum system that has two chambers separated by one valve. Chamber one stays under vacuum while chamber two goes to atmosphere for a period of time and then goes back down to vacuum, the valve is closed during the process. While this is happening chamber one will have a slight rise in pressure and chamber two will drop dramatically in pressure.

I would like to use an Arduino package to sense the outputs from two ion gauges, one on each chamber. The gauge output will be 10v to 0v and is linear relative to the pressure change. When the pressure (voltage reading) is the same for both gauges I want to send a signal to a 5v-24v ss relay that will open the valve between the two chambers and keep it open. I will also need to have some kind of button or input to close the valve and reset the Arduino so that it will check the outputs for the next time they cross over and then open the valve. I'm not concerned what the absolute pressure (gauge output) is, my main concern is that the two outputs are equal within the accuracy of the gauges when the valve is opened.
How do I go about doing this??? All suggestions, comments, and thoughts are welcome and appreciated.

Thank you for your help!

I can envisage a solution where you use a voltage divider to bring the sensor voltage down to the 0 … 5V range and the Arduino’s analog input pins to read the analog levels. The internal ADCs only give 10 bit resolution, and you will halve the resolution again with the voltage divider, giving you a best possible resolution of roughly 10 mV per bit. Is that going to be sufficient?

You can use a relay shield or motor driver plus external relay to operate the solenoid.

Assuming you can sort out the input and output circuits and power supplies etc, the basic logic you’re describing sounds extremely simple.