1. A computer program for troubleshooting a control program of a type comprised of instructions receiving input data from variables of the control program and measurements of physical inputs from an industrial process and providing output data to variables of the control program and output signals controlling the industrial process, the computer program fixed in a nontransient computer readable medium for execution on an electronic computer to: (1) output on a display associated with the electronic computer a representation of a first instruction showing a value of output data for the first instruction at a first time; and (2) accept a step instruction from a user changing the output on the display of the first instruction to jump to a second instruction at a second time; wherein the second instruction at the second time provides output data that is consumed directly or indirectly by the first instruction at the first time.