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PR-282 Differential Pressure Transducer


The PR-282 incorporates sophisticated integrated circuits and new fused silicon monolithic cavity pressure sensors to not only provide a high level, fully conditioned, and temperature compensated output, but also to offer up to six (6) pressure ranges. The stainless steel monolithic pressure cavity not only provides media compatibility for most of the applications, but also offers a leakproof solution for today's environmentally conscious customers. Three industry standard output versions are available: 4-20 mA 2-wire loop or 0-5 VDC/0-10 VDC. A wide 12-40 VDC or 12-35 VAC unregulated supply voltage and a broad 0°F - 180°F compensated temperature range ensures compatibility to most of the applications. A rugged NEMA-1 (IP-30) enclosure, fully temperature compensated NIST traceable accuracy and a liberal five year warranty are some of the features which make the PR-282 the industry's most reliable, rugged, and economical pressure sensor.

The PR-282 sensing elements are 100% solid-state piezoresistive silicon strain gauge fused directly onto the stainless steel monolithic pressure cavity. The pressure cavity is machined out of a solid rod and does not incorporate any welds, seams, or bonds. In this way, the sensor not only offers excellent linearity, repeatability, and sensitivity, but also exhibits negligible hysteresis and withstands significant overpressure without zero shift. The monolithic nature of the cavity ensures not only leakproof operation but also enhances the overpressure and burst pressure specifications. The pressure cavity design incorporates novel techniques to isolate the fused silicon sensing element from installation related stress thereby ensuring zero integrity. The stainless steel offers excellent media compatibility to most of the industrial and commercial applications.

The PR-282 incorporates sophisticated integrated circuits to provide a high level, fully conditioned and temperature compensated output.

MAMAC PR-282 has unique “Double D” design stainless steel ports. The sensing elements are welded to the ports and both have stainless steel isolation between the sensor and media. In HVAC applications, thermal shock has always been a problem. A rapid change in temperature may cause epoxy seals to break and 0-rings to blow out. The coefficient of thermal expansion of epoxy, neoprene and Buna-N is not the same as steel. A rapid temperature change will cause the ports and sensor to expand and the dissimilar coefficient of thermal expansion will result in the epoxy seals breaking and the 0-rings loosening resulting in a leak. The PR-282 with welded construction and all stainless steel pressure cavities performs reliably under thermal shock conditions.

Another problem well known in our industry is that if a bulkhead fitting is used to secure the sensor to the enclosure, overtightening the fitting will result in the sensor twisting and the lead wires may break or the calibration may shift. To eliminate this problem, our engineers have incorporated a unique Double D designport which is secured to the enclosure with two retaining E-rings. The Double D shape of the ports eliminates any possibility of the sensor twisting due to overtightening and the E-rings provide a rugged means to securely attach the sensing elements to the enclosure. The ports have wrench flats on each side to assist in tightening the pipe fitting to the ports.

The dual all stainless steel pressure cavities enable our PR-282 to be compatible to all media encountered in HVAC applications including freon, ammonia, steam, chilled/hot water, among others. This feature enables one unit to be compatible for all applications. On VDC output units, two options are available: outputs 0-5 or 0-10 VDC, and dual unregulated supply voltages 12-35 VAC or 12-40 VDC.

The mA output units can function over a wide unregulated supply voltage range of 12-40 VDC without any affect on calibration or performance. The unit has reverse polarity protection build in. As a result, it is next to impossible to damage the unit by mis-wiring. By using sophisticated low drop-out voltage regulators and CMOS integrated circuits, the mA output unit can drive very high output impedance. In fact, with only 12 VDC supply, the unit can drive 400 ohms. At 40 VDC, the unit is capable of handling up to 3000 ohms load. In this way, the output loop can be tied in series to multiple controllers, indicators and other devices without degrading the performance.

The PR-282 is shipped fully calibrated and tested with a minimum 24 hours burn-in to provide trouble free start up. Easily accessible zero and span trimmers are provided if field calibration is needed. The PR-282 has a unique 16 gage steel NEMA 1 enclosure designed to facilitate installation and provide easily accessible wiring termination. The pressure ports have industry standard 1/8-inch NPT process connection to accommodate any pipe fitting.

With more than 4 output and supply voltage options and 6 pressure ranges, our PR-282 not only guarantees compatibility to all control systems but also is the most reliable, stable and versatile differential pressure sensor available.