The paper presents the methodology of the logic controller development process based on the UML state machine diagram. The development process covers the logic synthesis and the implementation by means of the intermediate model based on Petri net formalism. The transformation between these two formal models is performed at the metamodels level according to the Model Driven Architecture (MDA). Semantics of the hierarchical configurable Petri net (HCfgPN) was adopted for the preemption and resumption mechanism. Operational subnet of HCfgPN model may be verified using formal methods.

This paper presents a design of a flow meter based on a programmable logic controller (PLC). The new construction of a flow meter controlled by PLC increases the possibilities for the control and automation of fluid flow. Additionally, the didactic potential of the use of simple automation in the form of a programmable logic controller was considered. A device enabling the measurement of fluid flow rate based on a PLC controller was designed, constructed, and tested. The choice of device was the Gems Sensors FT-210 series turbine flow sensor, which is characterized by low purchase and maintenance costs. The properties and the chemical resistance of polyamide-12, the material the sensor is made of, make it possible to test the flow of various types of fluids. As part of the work, an algorithm and a program controlling the device was developed based on the APB Soft software, enabling the accurate reading of the number of impulses sent by the turbine flow sensor. The results of the designed flow meter were compared with the results obtained for the Krohne VA-40 high accuracy rotameter.

This paper deals with a new approach to logic controllers developing process. Classic development approach assumes the use of only one chosen model for the purpose of a logic controller specification. The proper choice of a model is a critical issue because drawbacks, advantages and specific characteristics of a controller will directly or indirectly affect each stage of a development process. A logic controller specification will have an influence on each stage of a development and, first of all, on an end product - namely, a logic controller and its quality. Diversification of the specification through the application of the Correlated State Machine and Hierarchical Configurable Petri Net (CSMHCPN) dual model brings out advantages of both component models eliminating, at the same time, their drawbacks. This paper presents an alternative approach to design logic controllers where at the specification stage two complementary models were used.