MKS Baratron 122B, Инструкция по эксплуатации

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Chapter One: General Information Introduction
17
Chapter One: General Information
Introduction
The MKS Baratron
®
Type 122B Absolute Pressure Transducer continues the evolution of low
cost pressure measurement by providing a 15-pin Type “D” connector on the industry standard
122A unit. Using a latest-generation single-sided dual-electrode Inconel
®
sensor coupled with
a fixed-frequency bridge signal conditioner, the 122 provides operation which is inherently
temperature stable at zero pressure, capable of withstanding high overpressure conditions with
minimal or no shifts in output over its range, and high resistance to corrosive environments.
The variable-capacitance sensor is the result of over 25 years of research, development and
customer experience in total pressure measurement. The design incorporates a tensioned metal
diaphragm (Inconel), one side of which is exposed to the gas whose pressure is to be measured.
The other (reference) side of the diaphragm contains a dual electrode assembly (previously found
in premium transducers only) sealed in a high vacuum reference cavity which is maintained by a
chemical getter system.
The signal conditioning electronics board contains a fixed-frequency oscillator, balance-sensing
circuit, linearization circuitry and amplifiers which provide a 0 to 10 Volt DC full scale output.
The signal conditioner is inherently temperature stable at balance (pressure = 0 Torr) and is self-
compensating with temperature changes at other pressures.
A drawn aluminum can forms the protective cover for the transducer. The 15-pin Type “D”
connector allows connections to be easily made for ±15 VDC power inputs and the 0 to 10 VDC
pressure signal output. In addition, the aluminum cover works in conjunction with the metal
connector and an inner PC shield board with RF bypass capacitors to virtually eliminate RFI and
EMI.