Heater Controls

3Aug/080

Heater Controls

Custom Industrial Controllers Outperform PLCs

Written by Paul Nickelsberg, President and CTO of Orchid Technologies Engineering and Consulting, Inc.

Programmable Logic Controllers, PLCs, are used extensively for industrial control applications. PLCs provide the designer with a general processor architecture, a general input / output architecture, a general mechanical architecture, and a general software development architecture. Industrial designer engineers, factory automation engineers, or industrial controls developers may take advantage of generalized solutions for their particular needs.

There are times when the generalized architecture of PLCs is unsuitable. Perhaps the equipment to be controlled is sold in volume. Perhaps the equipment to be controlled must fit in a limited volume or space. Perhaps the equipment to be controlled requires the use of specialized sensors and instrumentation. Perhaps the equipment to be controlled requires simplified interconnection mechanisms. A customized industrial controller can save cost, save space, use specialized sensors and simplify deployment when compared with general purpose PLCs.

The cryogenic pump controller shown below was custom-developed by Orchid Technologies to solve a specific industrial control requirement. Controller size, safety, and reliability were paramount concerns. Cryogenic pump control makes use of highly specialized pressure and temperature sensors. Cryogenic pump control requires the execution of specially timed operational sequences. Motor systems, heating systems, liquid flow systems, must be precisely controlled. Commands are received from upstream factory automation equipment. Operator indicators provide early emergency-situation warnings.

Based upon a low-cost Freescale HCS12 processor, the cryogenic pump controller replaced thousands of dollars of general purpose PLC equipment. The single circuit board custom controller provided RS232 Communications, Network Communications, Real Time Clock services, AC Motor Control, AC Heater Control, two cryogenic temperature sensing channels, two low pressure sensors, and general purpose IO. Custom programming efficiently executes complex pump control sequences including purging, regeneration, temperature control and error detection. The single board controller is housed in a small water-proof NEMA-rated steel box.

Customized industrial control solutions, such as the cryopump controller, costs a fraction of what a comparable PLC solution might cost. Orchid Technologies Engineering and Consulting, Inc. has developed numerous custom industrial controllers. We work with our clients to carefully study their control requirements. We select from a variety of processor and sensor circuitry choices. We design and fabricate a custom solution to demanding control needs. Visit www.orchid-tech.com to learn more. Or call us at 978-461-2000 to discuss your particular needs.

About the Author

Paul Nickelsberg, President and CTO of Orchid Technologies Engineering and Consulting, Inc., has 20 years experience in electronic products design. He can be reached at paul@orchid-tech.com or 978-461-2000 X111.

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