This unit reads the temperature of the Liquor Tun and Boiler using Type E thermocouples. A thermistor is used for greater accuracy to measure the mash temperature.
Resistance is measured at the high and low level probes.
The HP34970A also switches 120 VAC to the sparge solenoid and the RIMS pump. The three burners are also controlled by switching 24 VAC to them.
My notebook PC uses an HPIB PCMCIA card and cable to communicate with the HP34970A. The System Software can read all sensors and control all actuators once per second. That's faster than I need to update things. I've been updating once every two seconds. Still a lot of data(200K) for a six hour brew. See the process graphs.