The using of operational automaton of transitions as the block of microinstruction addressing of compositional microprogram control unit is proposed. The new structure model of compositional microprogram control unit with reduced hardware amount is developed. The generalized structure of operational automaton of transitions is suggested. An example of process of synthesis of compositional microprogram control unit with operational automaton of transitions is given.
The paper presents a review of methods of implementing timers in Programmable Logic Controllers, along with a discussion of the timer properties. The authors focus on software implementations, as this approach has dominated practical solutions. An important part of the discussion is analysis of errors in time delay generation, and possible error sources. A typical case of a PLC generating a predefined time delay is analyzed. The discussion is concluded with recommendations on implementing timers, intended for PLC designers.
The method is proposed for reduction of hardware amount in logic circuit of Moore finite state machine implemented with PLAs. It is based on using classes of pseudoequivalent states. Each a class corresponds to a unique state of equivalent Mealy FSM. In this method the next state code is represented as a concatenation of codes for class of pseudoequivalent states and collection of output variables. Such an approach allows the elimination of dependence among states and output variables.
The paper shows the description of ontology which solves several issues. The first section of the paper shows general theory about ontology. We mention the definition of ontology and its use in automation technique. The OWL DL language which is mentioned in the first section is described here for our following work. The second part of the text shows the solution of two issues. The first one is the solution of the industrial automation device description. The article shows possible ways to the creation of the device description through the using of ontology. The second issue is a work with a lot of data which are used by modern devices. The paper shows a part of ontology which is used for data integration.
A new two-stage method of FSMs synthesis for PAL-based CPLD is proposed. It is based on both the wide fan-in of PAL cells and existence of the classes of pseudoequivalent states of Moore FSM. The first step targets decreasing for the number of PAL cells used for implementing the input memory functions. The second step targets decreasing for the number of PAL cells in the block of microoperations. An example of application of the proposed method is given, as well as, results of experiments carried out for standard benchmarks.
