The Model 535 process ¼ DIN PID process controller is designed to control any process variable, including temperature, pressure, flow and level, in batch and continuous processes. It has a sampling rate of 10 times/sec; universal process input; and modular, field-interchangeable outputs. It is equipped with an RS-485 serial communications interface for fast and accurate data transmission and is capable of sophisticated control algorithms, including the Powertune family of tuning algorithms. This family includes three unique versions of tuning: pretune, powerback and adaptive tuning.