Fast Designing Ladder Diagram of Programmable Logic Controller for a technological process

The article presents developed method and general principles of creating ladder diagrams, which are commonly used for systems with programmable logic controllers (PLC). Ladder diagrams are created for sequential control systems of technological processes, which are described by a connection pattern, time diagrams of the executive elements` operation. The executive elements are double-acting pneumatic or hydraulic actuators controlled by bistable electrovalves. A method of designing sequential systems enabling the creation of a ladder electro-pneumatic system is presented. The ladder diagram consists of two parts. One is responsible for controlling the valve coils, the other for the implementation of the memory block. The signals that control the transition to the next state are the signals described on the boundaries of the graph division. The synthesis of control systems and their verification was carried out using the computer aided program FluidSim by Festo

Fast Designing Ladder Diagram of Programmable Logic Controller for a technological process

The article presents developed method and general principles of creating ladder diagrams, which are commonly used for systems with programmable logic controllers (PLC). Ladder diagrams are created for sequential control systems of technological processes, which are described by a connection pattern, time diagrams of the executive elements` operation. The executive elements are double-acting pneumatic or hydraulic actuators controlled by bistable electrovalves. A method of designing sequential systems enabling the creation of a ladder electro-pneumatic system is presented. The ladder diagram consists of two parts. One is responsible for controlling the valve coils, the other for the implementation of the memory block. The signals that control the transition to the next state are the signals described on the boundaries of the graph division. The synthesis of control systems and their verification was carried out using the computer aided program FluidSim by Festo

Generic Dijkstra: correctness and tractability

The recently-proposed generic Dijkstra algorithm finds shortest paths in networks with continuous and contiguous resources. The algorithm was proposed in the context of optical networks, but is applicable to networks with finite and discrete resources. The algorithm was published without a proof of correctness, and with a minor shortcoming. We provide that missing proof and offer a correction to the shortcoming. To prove the algorithm correct, we generalize the Bellman's principle of optimality to algebraic structures with a partial ordering. We also argue the stated problem is tractable by analyzing the size of the search space in the worst-case

Is dynamic dedicated path protection tractable?

Intractable is the problem of finding two link-disjoint paths of minimal cost if the path cost is limited since it can be a special case of the partition problem. In optical networks, this limit can be introduced by the signal modulation reach. Even without this limit, the existing literature suggested the problem intractable because of the spectrum continuity and contiguity constraints, but we show that the problem can be solved exactly with the recently-proposed generic Dijkstra algorithm over a polynomially-bounded search space, thus proving the problem tractable

Addition of Di(trimethylsilyl) Phosphite to Schiff Bases of 2,5-Diformylfuran

A series of 2,5-Furanyl-bis-(aminomethylphosphonic Acids) has been synthesized by the addition of di(trimethylsilyl) phosphite to azomethine bond of achiral Schiff bases derved from 2,5-diformylfuran. The stereochemical aspect of this reaction has been studied and compared with the behaviour of achiral terephthalic Schiff bases in similar reaction. Whereas, addition to achiral terephthalic Schiff bases was found to be highly stereoselective, the analogous reaction with achiral 2,5-diformylfuran Schiff bases was stereoselective exclusively in the case when the substituent is benzyl.N/