1、英文原文DESIGN OF PLC NETWORKS USING REMOTE I/O MODULE BASED ON CONTROLLER AREA NETWORKP. Roengruen, T. Suesut, J! Tipsuwanporn, V. Kongratana and S. Kulphanich Faculty of Engineering, King Mongkuts Institute of Technology Ladkrabang, Bangkok Thailand Tel (662)-326-7346-7 ext 102 E-mail: ktvittaykmitl.a
2、c.th ABSTRACT In this paper, the design of the networks system through CAN bus is presented. To distribute the control points with a long distance and different located for the application to on - off electrical equipment by the remote I/O module. The controlling and communication between the PLC an
3、d the remote 110 modules are used by the CAN bus serial communication. In this paper, the experiment has been set up the maximum of 32 remote I/O modules. Each remote I/Os are linked to host PLC programmed for handling a interrupt request from any remote 110 independently. Therefore, the scanning ti
4、me of the controller not effects. By using this technique, the controller (PLC) can be efficiently applied to the several hundred meters 1. INTRODUCTION A programmable logic controller is widely used in the industrial control system. The development is proposed to expand the control points, develop
5、the instruction set for easier programming to more intelligence, the interfacing with the other system, the controlling with long distance. Controller Area Network (CAN) is a well-known bus technology in industrial communication system. Two versions of CAN differing in the size of the identifier exi
6、st that consist of CAN 2.0A with an 11-bit identifier and CAN 2.0B with a 29bit identifier. This paper focuses of CAN 2.0A providing a sufficient number of identifiers for design PLC with low cost network. The communication media used a twisted pair with the several hundred meters for each remote I/
7、O modules. Each of remote I/O modules consists of 16-bit digital input and 16-bit digital output, and the maximum of 32 remote I/O modules can be linked to host PLC mean that the maximum control points are of 512 points. The automatic control systems in industries have many kinds of field device (e.
8、g. sensor, actuators), and many kinds of process control. The field bus concept needed to combine the signals from many kinds of the process control equipment to be the same signal by digital communication. The traditional communication standards know as 4-20mAdc (e.g. transmitter, I/P transmitter).
9、 This standard provides for point-to-point connection, which consists of all information exchanged between field and control devices in both directions. The great number of field devices being used requires a lot of cables. This is the problem in installation and maintenance and the documentation wo
10、rk as well. The fieldbus concept is basically a digital communication, which is capable of interconnection field devices with control system in any process control environment. The fieldbus communication architecture in the term of node will be used to refer to a field device. The fieldbus devices h
11、ave wide varieties of field devices. There are simple devices such as the limit switches, relays, single-contact device and dumb actuators, smart sensor, the complex devices such as the programmable controllers, PID and loop controllers, etc. The fieldbus supervisor is the central controller that ta
12、kes the total responsibility for initializing the bus, establishing what devices are attached to it and monitoring its activities. In the past, incompatible vendor-specific fieldbus were frequently used. Many fieldbus systems today are open standard system. The user is no longer tied to individual v
13、endors and is able to select the best and most economical product from a wide variety of products. Today, all leading manufacturers of automation technology offer fieldbus interfaces for their devices. That is why the fieldbus systems present very dynamically growing branch of science and developmen
14、t directly applied in industry. These technologies are developed and administrated by user organizations (CAN in Automation, Open DeviceNet Vendor Association 8, Fieldbus Foundation 1,3, Profibus International 2,5 etc.). The popularity of CAN is due to its ease of use, to its extremely high efficien
15、cy and reliability and to the low costs of CAN implementations. Therefore, in this paper focuses on the Controller Area Network to design the PLC network. 2. CONTROLLER AREA NETWORK Electronic units began to equip vehicles in early 80s. Gradually, they increased the need for real-time communications
16、 with in a vehicle. However, adding more dedicated signal lines soon became impossible because of cost, reliability and repair problems. (The total length of cables in some high-end European cars released in the late 80s was estimated to be over 2 km!) To fulfill this sharp need for multiplexed communication, the “Robert Bosch GmbH” company designed the CAN network. Although specifically conceived for the automotive industry, it is widel
