IEC 61131-3 Programming

The engineering discipline "IEC 61131-3 Programming" covers all steps required for the development of the application code. This includes:

Definition of user-defined data types, such as ARRAYs, STRUCTs, STRINGs, etc.
Handling of POUs (Program Organization Units).
Development of the application code using the IEC 61131-3 standard programming languages FBD (Function Block Diagram), LD (Ladder Diagram), SFC (Sequential Function Chart), and ST (Structured Text). Code development also includes the declaration of variables.
Besides the classic free-graphic FBD/LD code, PLCnext Engineer supports a second variant of mixed FBD/LD networks referred to as NOLD (network-oriented Ladder Diagram).
Safety-related code is programmed in SNOLD (refer to the following section).
To support you in programming, the Cross Function Area at the lower window border provides several tools, such as the CROSS REFERENCES window.
Configuration of the controller runtime: definition of the task and event settings, the assignment of programs to tasks (program instantiation), etc.
Configuration of the Safety PLC runtime (if a Safety PLC is included): instantiation of exactly one program.

Safety-related IEC 61131-3 programming

PLCnext Engineer supports the complete implementation of a safety-related application if the controller involved includes a Safety PLC. With regard to functional safety, the engineering discipline "IEC 61131-3 Programming" includes the following:

Creation and programming of safety-related POUs.
Safety-related code is edited in the FBD/LD programming language in so-called SNOLD (Safety Network Oriented Ladder) worksheets. SNOLD is nearly identical to NOLD, apart from some safety-related peculiarities which are described in the corresponding help topics.
While editing code and variables in safety-related POUs, the respective editor performs a continuous verification of the worksheet data consistency. Any detected inconsistency (i.e., possible data corruptions) results in an editor error and a safety violation notification.
Instantiation of exactly one safety-related program in the single task executed by the Safety PLC. Both the safety-related task and the program instance are created automatically on insertion of a controller with a Safety PLC in the PLANT.
Assignment of safety-related I/Os.
Assignment of exchange variables which enable the communication between the standard controller and the safety-related PLC.

For editing safety-related parts of the project, you have to be logged on to the Safety-related Area. This is an area of responsibility restricted to authorized members.

Safety-related code and data processed in and generated by PLCnext Engineer is based on the IEC 61131-3 standard and meets the safety requirements defined in the standards IEC 61508, EN IEC 13849 and EN 62061 (depending on the project settings).

Further Info
Observe the descriptions in chapter "Safety-related information".