A method for designing ladder diagrams for sequencing tasks is described. it is systematic, fast, and simple to apply. The method is applicable to both programmable controllers and hard-wired relay circuits. While it ...
详细信息
A method for designing ladder diagrams for sequencing tasks is described. it is systematic, fast, and simple to apply. The method is applicable to both programmable controllers and hard-wired relay circuits. While it does not minimize the number of required relays, this should be no problem when working with programmable controllers. The method is based on the idea of dividing the required sequence into groups according to a simple rule. These groups are then encoded using the "one-hot" code, with each group assigned one relay set up to operate as RS-flip-flop. The various operations belonging to a particular group result each in a single ladder-diagram line. The method can also be adapted to systems with multiple-path programs having one or more random inputs. This is of special importance when using simple, low-cost programmable controllers, which usually do not provide conditional jumps. Four examples of such multi-path programs are presented: Two or more simultaneous parallel paths; two or more alternative parallel paths; option of by-passing certain steps; and option of repeating certain steps. The method has been used successfully in an instructional automation laboratory at the author's institute.
This paper describes prototype software for automatically generating control programs for discrete manufacturing systems from a high-level description of the process. The control logic is synthesized from a specificat...
详细信息
This paper describes prototype software for automatically generating control programs for discrete manufacturing systems from a high-level description of the process. The control logic is synthesized from a specification of the physical resource states required to execute each operation. The software described in this paper allows the user to enter a functional description of the system into a database containing the operation sequencing conditions and related actuator and sensor data for each stage of the process. This information is then used to automatically generate programs for the on-line control computers. The current implementation supports binary sensor and actuator signals and generates control programs in Instruction List, a generic programming language for programmable logic controllers. The methodology is illustrated for the control of a conveyor system in an existing automated painting facility
The draft IEC standard for programmable controllers contains the elements necessary for the introduction of modern programming practices for the control of processes and machines, while retaining the ease of use of tr...
详细信息
The draft IEC standard for programmable controllers contains the elements necessary for the introduction of modern programming practices for the control of processes and machines, while retaining the ease of use of tr...
详细信息
The draft IEC standard for programmable controllers contains the elements necessary for the introduction of modern programming practices for the control of processes and machines, while retaining the ease of use of traditional graphical programming languages. Widespread acceptance of the standard will lead to increased readability, reliability, and maintainability of control programs. Advanced graphic programming environments and new programmable controller architectures will be required to make optimal use of the new approaches which will be made possible when the standard is finally adopted.
A binary decision controller is a programmable logic device whose use falls between that of hard-wired logic and microcomputer controllers. The paper explores the use of this type of controller for a number of simple ...
详细信息
A binary decision controller is a programmable logic device whose use falls between that of hard-wired logic and microcomputer controllers. The paper explores the use of this type of controller for a number of simple tasks.
This synchronous motor drive, unlike the DC link convertor drive, has a single mode of operation from starting to above synchronous speeds. The simple control scheme requires synchronism to the supply waveforms and ro...
详细信息
This synchronous motor drive, unlike the DC link convertor drive, has a single mode of operation from starting to above synchronous speeds. The simple control scheme requires synchronism to the supply waveforms and rotor position. Hardware, software and interface circuits for a Z80 microprocessor-based controller are described. A modest clock rate of 2.5 MHz is sufficient and still leaves the microprocessor 88% idle. High levels of control, and possibly some diagnostic features, can therefore be included.
This paper describes an experimental high level language-based digital drive controller for use in numerical control and robot control systems as well as in general single and multiple drive systems. The controller is...
详细信息
This paper describes an experimental high level language-based digital drive controller for use in numerical control and robot control systems as well as in general single and multiple drive systems. The controller is designed to replace conventional modular analog control systems. The controller directly executes a high level application-oriented graphic language ideal for real-time control in industrial automation. The high level language makes it possible for the user to configure the controller to his control application without difficulty, so reducing software costs significantly. A new architecture designed for high execution speed and a microprogrammed operating system allow the controller to be used for all control loops and also logic tasks in high performance multi-drive systems. Typical configurations for a d.c. motor controller are shown and experimental results are described.
暂无评论