Universal electric controllers are used to control process variables such as flow, level, pressure, and temperature in single or dual-loop operations. The controllers can take in 4-20mA analog input signals and RTDs, or thermocouples directly. The controller compares the input to a setpoint. As the input deviates from the setpoint, the controller sends an analog or digital signal to a device such as a control valve that operates to bring the measured unit back to the setpoint. Many controllers have RS-485 interface so they can be used with personal computers or larger systems.