On/Off controllers are also known as digital or electronic thermostats. Unlike PID controllers they do not require autotuning and offer simplicity of installation and operation. The number of available contacts for switching is the last digit of the Novus product number. N321 is a single relay contact, whereas N322 has two relay contacts.

Typically one contact is used for primary switching of the control device and the second contact can be assigned to alarms or performing an auxiliary function. Each relay output has an independent setpoint.