SEQUENCE DISPLAY APPARATUS AND METHOD

A sequence display apparatus including a sequence control circuit, a cathode ray tube control device and a sequence display control device is disclosed in which a keyboard included in the sequence display control device is provided with logical function specifying keys for specifying one of a plurality of logical functions corresponding to such logical circuits as AND, OR and flip-flop circuits and a timer and with keys for inputting the names of input signals and the name of an output signal. One logic function, all of the names of the input signals and the name of the output signal are inputted as one set by the key-in operation, each of a group of command codes which are determined by the kind of logical function and the number of the names of input signals, is added to a corresponding one of the names of the input signals and the name of the output signal which have been inputted, to compose a logical operation program. The names of input signals are collectively displayed at a left end part of the display surface of a cathode ray tube, a position on the display surface for displaying the logic symbol is determined in accordance with the number of input signals, and the arrangement of a line for connecting each of the names of the input signals and the logic symbol is determined on the basis of the state of the display at each of the picture elements forming the display surface.