Sequence instruction display system

A sequence instruction display system for use with a sequence controller having a program memory for storing a sequence program composed of a plurality of test and output instructions, said display system comprising:

• program storage means;
• address designation means manually operable for selectively designating the addresses of input and output elements connected to said sequence controller;
• control command means manually operable for selectively generating first, second, third and fourth commands;
• instruction display means for displaying said test and output instructions one at a time;
• state display means for displaying the ON-OFF state of any one of said input and output elements which is the objective of a test or output instruction being displayed on said instruction display means;
• a data processor coupled to said sequence controller, said program storage means, said address designation means, said control command means, said instruction display means and said state display means, including:
• first control means responsive to said first command from said control command means for applying an interrupt to said sequence controller so as to transfer said sequence program from said program memory of said sequence controller to said program storage means;
• second control means responsive to address data from said address designation means and said second command from said control command means for searching said program storage means for an output instruction having said address data designated by said address designation means so as to display said searched output instruction on said instruction display means;
• third control means for searching said program storage means for a number of test instructions which relate to the energization of an output element having said designated address so as to display successively said searched test instructions on said instruction display means when repeatedly given said third command from said control command means;
• fourth control means responsive to said fourth command from said control command means for searching said program storage means for an output intruction programmed for operating an output element for which a test instruction is being displayed on said intruction display means, so as to display said searched output instruction on said instruction display means;
• and
• fifth control means responsive to said third command from said control command means for applying an interrupt to said sequence controller so as to read the ON-OFF state of any input element for which a test instruction is being displayed on said instruction display means and to display said read ON-OFF state on said state display means.