The safety editor integrated in TwinCAT 3 allows the implementation of a safety application in a graphical environment. The desired logic is programmed according to a function block diagram (FBD). The application can be represented in the network infrastructures for increased clarity. The functions blocks known from the logic components can be used as logic elements (digital function blocks for EL69xx; additional analog function blocks for EL6910, EJ6910, EK1960, AX8xxx-x1xx, AX8xxx-x2xx etc.).
The safety editor offers increased flexibility and portability. This is achieved by initially programming independently of the actual hardware used. To this end, both the target system and all input and output devices are made available as so-called alias devices. At this level, all safety-relevant settings can be selected in advance. Before the project is finally transferred to the executing hardware, these alias devices must be assigned to the actually installed physical devices.
In addition to using pre-specified function blocks, there is also the possibility to create custom function blocks. These can be created by combining existing – pre-certified – function blocks or by using Safety C (this can only be done for the safety runtime). Safety C is an almost unrestricted derivative of standard C. This allows well-known control structures such as IF-THEN-ELSE, SWITCH CASE and the data types usual in C to be used for safety applications.
An important novelty in the programming of safety-relevant applications in TwinCAT 3 is the extended user management.