Process industry users needlessly uneasy about PLCs for control

Just 20% more process industry users now believe that programmable logic controllers (PLCs), developed for discrete manufacturing automation, are suitable for process control than did three years ago. Yet a recent European survey conducted by IMS Research found nearly 90% of process PLC users happy with their direct analogue control facilities. The results suggest that the investment made by leading PLC manufacturers to improve the process control capability of their products has paid off, but that user education remains a big issue. Preaching to the converted is not going to open doors for PLCs to take over the process controller market. IMS analyst John Devlin says: “Despite the increased confidence in the capabilities of PLCs, it does not appear that customers within the process sectors will start to use them instead of a DCS (conventional process industry distributed control system), or hybrid controller en masse. “In fact, the companies surveyed expected their use of PLCs to hardly change over the next three years.” The survey also showed similar results for DCSs. Only PC-based controllers were expected to see notable increased use by the end of 2004.