A control program execution unit, when a callee control program is called, stores a return address in a stack and stores input data for the callee control program in a data storage unit. An execution error information management unit, when an execution error occurs, acquires execution error information that includes the return address stored in the stack, the input data stored in the data storage unit, and a program name that corresponds to the return address and is obtained by using mapping information that indicates the storing positions of a control program and the callee control program in a user program storage unit.

Disclosed embodiments include a method of using a general-purpose microprocessor to debug a programmable logic controller. In some embodiments, the method includes: at a MPU of the PLC, backing up identification information and file information of an interrupt step of steps comprised in a user's program and substituting the interrupt step with an exceptional interrupt code to set the interrupt step for the debugging; and at the MPU of the PLC, interrupting the driving of the PLC at a step including the exceptional interrupt code in executing the user's program step by step while driving the PLC.

A programmable display includes a display, a volatile memory, a nonvolatile memory that stores control screen data containing screen data, and a controller that loads the control screen data from the nonvolatile memory into the volatile memory at startup and displays a screen on the display on the basis of control screen data loaded into the volatile memory. The controller has a function to store the control screen data received from a screen data creation device in the nonvolatile memory and a function to store the control screen data received from the screen data creation device directly in the volatile memory.

An input-output data collector collects, from a programmable logic controller, input-output data representing a log for a device in a program predetermined as a logging target program of one or more programs executable by the programmable logic controller. An input-output data generator generates, when a debugging target program is determined not to be included in the predetermined program, input-output data representing a log for a device in the debugging target program by executing a simulation program simulating an operation of the programmable logic controller.

For automated verification of appliance procedures using a processor device in a computing environment, a testing configuration is dynamically configured for automatically testing software by adding and/or removing at least one application device from one of the testing configurations for creating a plurality of appliance configurations.

An input-output data collector collects, from a programmable logic controller, input-output data representing a log for a device in a program predetermined as a logging target program of one or more programs executable by the programmable logic controller. An input-output data generator generates, when a debugging target program is determined not to be included in the predetermined program, input-output data representing a log for a device in the debugging target program by executing a simulation program simulating an operation of the programmable logic controller.

A programmable controller includes a parameter manager to manage a parameter including an operation mode setting indicating whether an operation mode of the programmable controller is an active mode or a debug mode, and a character string data outputter to output character string data based on a message output command included in a program in the programmable controller. The message output command includes a first argument specifying whether a command is to be executed when the operation mode is the active mode or to be executed when the operation mode is the debug mode. The character string data outputter outputs or does not output the character string data to a preset destination, based on a result of a comparison between the operation mode setting and the first argument.

A method for synchronizing sensor data from an industrial process with program trace data from a control program executed by a programmable logic controller (PLC) controlling the industrial process. The method includes executing a control program to control industrial equipment and receiving sensor data based on physical responses from various sensors. Program trace data from the control program and sensor data is recorded during execution. The program trace data and the sensor data are time-stamped. Instances of the time-stamped program trace data and sensor data are synchronized. The synchronized data may then be replayed alongside the program trace data as the program is re-executed to allow a programmer to perform debugging.