The Timer Controller DCT 500 was designed for ease of installation in your dust collector system. For installations requiring fewer channels than are available on the board, a shorting plug is provided to allow selection of the last used channel. The time-on and time-off settings are selected using two potentiometers. High-limit and low-limit control inputs are provided for use with on-demand systems. When used in a continuous mode, the high-limit input is jumpered. For safety, the control circuitry, including the control inputs and the last channel jumper, is isolated from the power line.