MKS Baratron 121A, Инструкция по эксплуатации, Страница: 27 / 62

Chapter One: General Information Introduction
17
Chapter One: General Information
Introduction
The MKS Baratron
®
Type 121A Absolute Pressure Transducer is a precision pressure
measurement instrument that operates on a variable capacitance technique. This measurement
technique converts pressure to a linear DC output voltage using three components: a sensor,
signal conditioner, and power supply/readout unit. The Type 121 Pressure Transducer contains
two of the components: the sensor and signal conditioner. An MKS (or MKS-compatible)
power supply is required to complete the pressure-to-DC output voltage conversion, and an MKS
(or MKS-compatible) display unit can be used for direct pressure readout. The 121 instrument is
available in ranges from 1 to 25,000 Torr (mmHg). The Type 121 instrument measures down to
1x10-
4
Torr (1 Torr Full Scale).
In addition to the sensor and remote electronics unit (signal conditioner), the 121 instrument has
a shielded cable (8 ft. standard length) with a Type “D” connector attached to it. The separate
housings of the sensor and electronics unit enable the sensor to be heated to 150° C and allow the
electronics unit to be mounted in a convenient location. The shielded cable and connector
provide maximum zero stability, therefore requiring less adjustment. The cable is also easily
disconnected from the sensor when preparing the instrument to operate in temperatures up to
200° C (for maximum bakeout).
The Type 121 Absolute Pressure Transducer also has the following standard features:
•
Sensor constructed with all-Inconel
®
for corrosion resistance
•
Total pressure measurement range of over four-decades
•
High level 0 to 10 VDC output linear with pressure
•
Dual electrode bridge circuit design for maximum zero stability