Series 2000: Taking the cost out of the industrial pressure transducer

Abstract

A package of innovative concepts has been put together to develop the Series 2000 pressure transducer, which is being launched on the market in 1991. These concepts are aimed at a dramatic reduction in the manufacturing cost of a stainless-steel pressure port device and are: (1) Polysilicon on stainless-steel thin-film gauges for a high output from a simple, moderately stressed structure, with dielectric sensor isolation. (2) Stainless-steel sensor beams, with integral force rods, processed in wafer form and then sawn apart after probe testing (100+ sensors per wafer). (3) Vacuum brazed, rather than electron beam welded, pressure port/diaphragm assembly. (4) Direct mounting of the sensor beam onto the diaphragm by an advanced welding technique, giving a rigid, creep-free fixture with minimal heating of the gauge structure. (5) Complete assembly prior to compensation tests and trim. (6) Highly automated compensation using data logging, disc databases and bar code identification. The final result is a pressure transducer with excellent media compatibility, immunity to shock and vibration and good thermal performance, at a price considerably below that of previous transducers of this standard, and in a very compact housing approximately 6 cm long and 2.5 cm in diameter. Electronically interfaced versions have also been developed with standard 0–5 V or 4–20 mA outputs, without any significant increase in this package size. This paper presents constructional details, characterization results, and an overview of the automated manufacturing equipment installed to make this novel transducer.