Electric controller with selectable manual and automatic modes - has mode selection knob which also adjusts potentiometer

摘要

The controller is mounted in a simple rectangular chassis on the face of which are a set point dial, a controlled variable-amplitude display and a mode selection knob. This knob may be moved laterally to select one of the two modes. The knob is attached to a shaft (10) inside the chassis. At the end of the shaft is a potentiometer. Rotating the knob affects the potentiometer setting, providing an output for the control circuit. Lateral movement of the knob results in the shaft actuating a pair of switches (18, 19) which are connected to a relay driving circuit containing two or more relays, which give the appropriate circuit changes when a manual to automatic change, or vice versa, is made.