Abstract: A digital computer implemented software system is provided which translates a control program into a graphical flow chart and displays the same upon a visual display attached to the digital computer during execution of a control program. The graphical flow chart includes multiple flow paths of execution, each flow path having a respectively associated binary memory location. Each memory location has an initial value of zero, and the value of a particular memory location increases to one upon execution of the control program along the flow path associated with that particular memory location. When a memory location has a value of one, the flow path associated therewith is visually enhanced upon the visually displayed graphical flow chart. A user is provided with a function to reset each memory location value to zero at any time during execution of the control program.

Abstract: A digital computer implemented software system is provided for enabling on-line programming changes of industrial logic controllers using a software package of the type utilizing graphical flowcharts is provided, allowing a user to modify a program and transfer industrial process state information while the program is controlling equipment. A control program has predetermined stop points of execution. Each stop point is assigned a unique index used to retrieve instruction addresses from an array. Each stop point also is associated with industrial process state information. By substituting new addresses pointing to stop points in a new program for the executing program addresses and transferring the state information, the executing program is replaced by a new program when execution continues on the next CPU scan.

Abstract: A digital computer implemented software system is provided for programming industrial logic controllers using a software package of the type utilizing relay ladder logic to represent control programs. The control program is executable by the controller to control the operation of one or more industrial devices. Using relay ladder logic, the control programmer is provided with a system to replace a coil with an ACTION block containing at least one complex expression. When the left side of the ACTION block is energized, the expression is evaluated. In a further embodiment, the programmer is able to replace a contact with a DECISION block containing a Boolean expression. When the left side of the DECISION block is energized, the Boolean expression is evaluated. If the expression evaluates as TRUE, the right side of the DECISION is energized.