Provided is a simulation technique that allows the program verification to be more efficiently performed. A simulation system includes: a simulator that executes simulation of an operation of one or more devices; a data input unit that obtains one or more execution times in the simulation, positional information of each one of objects in the simulation, and a value of each one of one or more variables referred to by a program to operate the devices; a data recorder that stores, as a first log, positional information of the objects and value of the variables for each of the one or more execution times in a manner that positional information and value are associated with each other; and a displayer that displays positional information of the objects and value of the variables for each of the one or more execution times included in first log.

The present invention relates to a method for automatic translation of ladder logic to a SMT-based model checker in a network comprising defining (10) the topology of the network as an enriched network topology based on packets exchanged in the network, extracting (20) a program from the packets relating to a PLC in the network and identifying inputs, outputs, variables and a ladder diagram of the PLC, translating (30) the inputs, outputs, variables and ladder diagram into a predefined formal model, wherein the predefined formal model is a circuit-like SMT-based model checker, and wherein the translating (30) comprises translating the set of data types of the program according to a predefined model set of data types of the circuit-like SMT-based model checker, translating the inputs of the PLC as model inputs of the circuit-like SMT-based model checker of the same type, translating the outputs of the PLC as model output latches of the circuit-like SMT-based model checker of the same type, translating the variables of the PLC as model variable latches of the circuit-like SMT-based model checker of the same type, translating comparators and arithmetic operators of the ladder diagram into a plurality of predefined model functions of the circuit-like SMT-based model checker, translating contacts and coils of the ladder diagram according to predefined model recursive procedures relating to the predefined model set of data types, the model inputs, the model output latches, the model variable latches and the plurality of predefined model functions, wherein the contacts are switches that can block or allow the flow of the current in a connection and each of the contacts is controlled by a Boolean input or variable, and wherein the coils are assignments to Boolean variables.

An engineering tool includes a program display/editing unit that edits an official program to be run as an actual product and a debugging program to be used at the time of operation confirmation of the official program distinctively in such a manner that the debugging program is executed by a controller when the debugging program is selected and that the official program is executed by the controller without the debugging program being executed when the debugging program is not selected.

It is disclosed a PLC Program analysis method where a program (PROG) is translated (TRANS) into a model (MOD) in a logical framework, from which properties (Prop) are determined. Said properties coupled with user specifications (IntProp) are verified by an automated solver (SMT). If contraposition of a property (Prop) is satisfiable, counter-examples (PROOF NOK) representative of model inputs and internal memory values is provided. Counter-examples (PROOF NOK) are translated into error initial configurations (IniConf) of said model. Execution of the model is simulated (EXE) with said model error initial configurations (IniConf), and error intermediary configurations (AST-IntConf) of said model simulation are recorded up to said property violation. Error initial and intermediary configurations (Lad-IniConf, Lad-IntConf) of said original program (PROG) are derived from error initial configurations (IniConf) of said model and error intermediary configurations (AST-IntConf) of said model simulation and displayed. An apparatus for executing said method is provided.

A tracing apparatus that is connected to a PLC for inputting and outputting signals based on a ladder program includes: a ladder program analysis unit that analyzes an order in which nets in the ladder program are arranged so as to produce an execution order signal table indicating an order in which the nets are executed; a trace target setting unit that sets one or more nets to be traced; a trace data acquisition unit that acquires trace data in a predetermined sampling cycle; a compensation determination unit that determines, based on the table, whether or not the state (reference signal) of a signal at a contact included in a ladder circuit to be traced needs to be compensated for; and an output unit that outputs a ladder diagram of a trace result which has been compensated for based on the result of the determination of the compensation determination unit.

Disclosed systems and methods for enabling data to be transmitted between program modules based on compliance with rules, the method comprising: monitoring, by a security module executable by a processor, an interaction between a first program module and a second program module to determine whether the interaction complies with at least one rule, wherein the first program module is a source of data being exchanged with the second program module which is a recipient of the data, when the interaction does not comply with the at least one rule, modifying the data being exchanged between the source and the recipient of the data, and when the interaction complies with the at least one rule, allowing the data to be transmitted to the recipient.

The present invention relates to a computer program for producing a graphical user interface (100) of a manipulator program and to a method for navigation through a manipulator program, wherein the manipulator system (1) controlled by the manipulator program comprises at least one manipulator (30). The manipulator program comprises at least one set-down point (AP1 to AP5). The user interface (100) has a graphical program progress indicator (150) which indicates the current program progress of the manipulator program and the at least one set-down point (AP1 to AP5) of the manipulator program. The at least one set-down point (AP1 to AP5) indicated can be selected by a user, and the manipulator program is set up to control the manipulator system (1) in such a manner that the system assumes a system state assigned to the selected set-down point (AP1 to AP5) in response to the selection. The method comprises the steps of: providing a manipulator program; producing the graphical user interface; stopping the manipulator program; receiving a selection of a set-down point on the program progress indicator of the graphical user interface; and guiding the manipulator program to the selected set-down point, with the result that the manipulator program controls the manipulator system in such a manner that the system assumes the system state assigned to the selected set-down point. Such navigation may be advantageous, in particular, in the field of debugging, error correction and parameter correction or parameter optimization.

A controller of a PC displays program elements of a ladder program and an electrical connection state thereof on a display, detects an instruction designating a first program element, determines whether the first program element is in an electrically connected state or an electrically disconnected state, specifies one or more causal elements according to whether the first program element is in an electrically connected state or an electrically disconnected state, and displays the specified one or more causal elements on the display in a state discernible from other program elements.

Disclosed systems and methods for enabling data to be transmitted between program modules based on compliance with rules, the method comprising: monitoring, by a security module executable by a processor, an interaction between a first program module and a second program module to determine whether the interaction complies with at least one rule, wherein the first program module is a source of data being exchanged with the second program module which is a recipient of the data, when the interaction does not comply with the at least one rule, modifying the data being exchanged between the source and the recipient of the data, and when the interaction complies with the at least one rule, allowing the data to be transmitted to the recipient.

A tracing apparatus that is connected to a PLC for inputting and outputting signals based on a ladder program includes: a ladder program analysis unit that analyzes an order in which nets in the ladder program are arranged so as to produce an execution order signal table indicating an order in which the nets are executed; a trace target setting unit that sets one or more nets to be traced; a trace data acquisition unit that acquires trace data in a predetermined sampling cycle; a compensation determination unit that determines, based on the table, whether or not the state (reference signal) of a signal at a contact included in a ladder circuit to be traced needs to be compensated for; and an output unit that outputs a ladder diagram of a trace result which has been compensated for based on the result of the determination of the compensation determination unit.