June 12, 2005
June 12, 2005
June 15, 2005
10.1225.1 - 10.1225.9
Teaching PLCs with the IEC 61131 Standard Languages
James Rehg, Bruce Muller Penn State Altoona
Programmable Logic Controllers are the de facto standard for sequential control of discrete automation systems and are fast becoming the system of choice for control of analog process systems. The new languages introduced in the IEC 61131 PLC standard will increase the number of applications suitable for PLC control. This paper provides a description of the new standard and describes a laboratory at Penn State Altoona that supports a two course sequence for PLC. The laboratory has 16 student stations and 4 automated assembly systems linked by an Ethernet LAN with a DeviceNet sub-network. The laboratory supports ladder logic programming using SLC 500 system technology for an introduction to PLC concepts taught in the first course. The second course includes programming in five of the IEC 61131 languages (ladder logic, structured text, function block diagrams, and sequential function chart languages) on an automated assembly system using a DeviceNet LAN and DeviceNet compatible control devices. In addition, the paper describes how the different languages were used and introduced.
Introduction to the IEC 61131 PLC Standard
The first standard for PLCs was published in 1978 by the National Electrical Manufacturers Association (NEMA). However, the rapid growth in PLCs across national boundaries demanded a broader standard. In 1979 the International Electrotechnical Commission (IEC) established a working group to look at the complete standardization of PLCs1. The PLC standard, called IEC 1131, (changed later to IEC 61131) has the following parts.
Part 1: General information establishes the definitions and identifies the principal characteristics relevant to the selection and application of programmable controllers and their associated peripherals. Part 2: Equipment requirements and tests specifies equipment requirements and related tests for programmable controllers (PLC) and their associated peripherals. Part 3: Programming languages defines, as a minimum set, the basic programming elements, syntactic and semantic rules for the most commonly used programming languages, as well as major fields of application, applicable tests and means by which manufacturers may expand or adapt those basic sets to their own programmable controller implementations. Five PLC languages are defined. Part 4: User guidelines a technical report providing general overview information and application guidelines of the standard for the end user of programmable
“Proceedings of the 2005 American Society for Engineering Education Annual Conference & Exposition Copyright 2005, American Society for Engineering Education”
Rehg, J., & Muller, B. (2005, June), Teaching Plcs With The Iec 61131 Standard Languages Paper presented at 2005 Annual Conference, Portland, Oregon. https://peer.asee.org/15459
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