Switching matrix for automatic or manual control - has switches on matrix input enabling selection of location mode

摘要

A control matrix comprises four rows of wires and four columns with a control winding series with a diode between each row and column wire. The centre pole of a three position switch is connected to each row and column wire. The switches connect the wires to a fixed input voltage, this being a manual operating position enabling manual switches to be operated, or to earth, this being the rest position. The third position is the automatic control position and connects to a two input gate each having a control input.