Overview

Considerable progress in the adoption of IEC 1131-3 languages has been made in the three years since this book was first published in 1995. At that time, the PLCopen trade association promoting IEC 1131-3 products had a membership of about 40 companies and organisations. Now in the spring of 1998, PLCopen's membership has grown to almost 100 indicating that interest in IEC 1131-3 is rapidly increasing. Most of the major PLC manufacturers now have an active interest in IEC 1131-3. Originally the main interest in IEC 1131-3 was centred in Europe, but interest is now truly international with involvement of companies from the US, Japan and Europe.

Since 1993 a wide range of automation products have appeared on the market that have adopted some aspects of the IEC 1131-3 standard; these range from programming support software for traditional ladder based PLCs, through to soft PLC products, and programmable SCADA.

Worldwide, the market for PLCs and automation products is still showing healthy growth. Related to this growth in automation, there is also going to be a considerable increase in the demand for software. It is estimated that the European market alone for automation and process control software will be at least $2500 million by 2001. It is therefore likely that the demand for IEC 1131-3 based products is also going to increase dramatically.

As companies started to develop products complying with the 1993 edition of IEC 1131-3, small inconsistencies and errors in the standard were uncovered. The IEC task force,...