PLC/PAC product research released
Oak Brook, IL– Control Engineering has released the results of its 2008 survey of subscriber purchase and application of programmable logic controllers (PLCs) and programmable automation controllers (PACs). Highlights of the findings include:
• Almost 40% of the average respondent’s installed PLCs / PACs are micro (15 to 128 I/O points). Medium PLCs/PACs (128 to 512 I/O) are installed by about one-third of respondents. In addition, 49% of PLC / PAC type devices installed are used as an embedded controller with 23% mentioning they are used as a data logger or SCADA application connected to a PC.
• Machine control is the most prominent application of PLCs/PACs at respondents’ locations. Process control is applied at three-fourth of locations. Almost one in three respondents report having PLCs/PACs that are networked with other PLCs. However, only 3% are networked with other PACs.
• Serial RS-232/RS-485, 4-20 mA/0-10 V dc, and Ethernet protocol are currently the most widely used means of communications with PLCs/PACs.
• Currently, the term PAC represents different things to different people. However, 37% of respondents say they are supplementing or replacing their PLC usage with PACs.
• Virtually all respondents use ladder diagrams to program PLCs/PACs. This is almost double the usage of any other programming language.
• Built-in communication support is the most important feature to survey participants when buying a PLC/PAC. Product features less important in selecting PLCs/PACs include cellular remote connectivity, hand-held setup tools, and nano controllers.
Control Engineering provides an
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– David Greenfield , editorial director
Control Engineering News Desk
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