Programmable Logic Controllers Product Research, December 2005

Research was undertaken to gain a better understanding of Control Engineering subscribers’applications and needs regarding Programmable Logic Controllers.

By Control Engineering Staff December 7, 2005

Research was undertaken to gain a better understanding of Control Engineering subscribers’applications and needs regarding Programmable Logic Controllers.

Executive Summary

Among those specifying, recommending, and/or buying Programmable Logic Controllers, 74% do so for in-plant requirements and 43% buy for OEM needs.

  • One-third of the average respondent’s installed PLCs are Micro PLCs (15 to 128 I/O). Medium PLCs (128 to 512 I/O) are a close second.

  • Machine control is the most prominent application of PLCs at respondents’ locations. o One in three respondents report their PLCs stand alone. Over one-fourth of respondents indicate their PLCs network with personal computers (PCs).

  • Serial RS-232/RS-485 and 4-20 mA/0-10 V dc are currently the most widely used communication protocols.

  • Among those who use Ethernet, 67% use it as a supervisory network. Nearly two-thirds use it to network PLCs. Among those who use Ethernet, 75% use TCP/IP as their protocol. EtherNet/IP is the second most popular protocol among this segment.

  • Virtually all respondents use ladder diagrams to program PLCs. This is nearly triple the usage of any other programming language.

  • Built-in communication support is clearly the most important factor to survey participants when buying a programmable logic controller CPU.

  • Universal programming software for multiple hardware targets/platforms narrowly edges out PLC I/O networked to PCs as the most anticipated feature in future PLC purchases.

  • Analog, discrete, and communication are the most widely used I/O modules among those surveyed.

  • The term PAC currently represents different things to different people. A PC-based processor in a rugged PLClike package is the most widely accepted description for programmable automation controllers (PACs). However, nearly as many consider a PAC to be like a PLC, but more “open”.

  • Rockwell Automation, by a wide margin, tops the list of PLC manufacturers purchased from in the past 12 months. Twenty-nine PLCs was the average number each survey participant purchased during the past 12 months. The average spending per respondent on PLCs in the past year was $106,437.

  • One out of two respondents report their purchases of PLCs will grow in the next 12 months, while only 8% expect a decline.

  • Virtually all of those surveyed are satisfied with their suppliers, with over half being very satisfied.

Programmable Logic Controllers Product Research 2005