MSFC: Extension of the IEC 61131 language SFC

In addition to the IEC languages, the programming language MSFC (Machine Sequential Function Chart language) is supported, an extension of the language SFC.

MSFC is mainly used in the automotive sector and unites cross-system diagnose capability with easy operation, which results in high availability of the systems.

Step sequences, types and operating modes: MSFC in short...

As in the IEC language SFC (Sequential Function Chart language), the machine cycle which is to be realized in the control software is defined in a flow chart. In this flow chart all single movements and their dependencies are explicitly and implicitly represented. Additional requirements for the control software result from the sensor technology, the actuators and constructional demands.

In the flow chart the machine cycle is divided into functional units, the steps. Between the single steps a chronological and/or a functional relation exists. In MSFC this relationship is represented by arranging steps graphically in one or several step sequences. To reduce the programming effort for the control software, different types of steps are available in MSFC. The step type determines the functional characteristics of a step, including some processing rules and properties for supervision and diagnostics. These characteristics are realized by the programming system and do not have to be programmed by the application programmer.

Operating modes: In MSFC, different operating modes can be used: Automatic mode, automatic step mode, manual mode and set up mode. This way, apart from the normal operating procedure, the most suitable operating mode is available for each situation during the life of the system, like for example commissioning or troubleshooting. The step sequences and the step inherent functionality is processed according to the selected operating mode.

Supervision and diagnostics: Having started the machine or system operation, it is necessary to monitor the system cycles which are executed. In case of machine failures it is necessary to display the cause of the failure, i.e. the corresponding step, or the failed I/O signal. Therefore, the following options for monitoring and diagnostics have been implemented in MSFC, e.g. monitoring functions during operation (text output), issuing of step priorities, criteria analysis etc.