Drawing Number: 21088
Revision: NR
OPERATION MANUAL FOR
ICP
INDUSTRIAL PRESSURE SENSOR
Series 121
Models 121A21, 121A22, 121A23, 121A24
Models 121A31, 121A32, 121A33, 121A34
1
1.0
INTRODUCTION
The Series 121 consists of eight ruggedized quartz
sensors designed for dynamic pressure measurements
in harsh environments. Models 121A21-24 have two-
pin MIL connectors, and Models 121A31-34 are
provided with a molded integral cables, 10 feet (3 m)
long.
The high impedance voltage signal produced by the
quartz element in the Series 121 is impressed across
the input of a built-in miniature source follower
amplifier (actually an impedance converter with unity
voltage gain) which converts the signal a low
impedance voltage less than 100
, able to be fed
directly
into
readout
instruments
such
as
oscilloscopes, peak meters, etc. over long cables.
Series 121 are designed for permanent installation by
Original Equipment Manufacturers in pumps,
compressors and pipelines for monitoring pressure
fluctuations and/or surges.
Series 121A20 Industrial Pressure Sensor
Series 121A30 Industrial Pressure Sensor
The models are dimensionally the same, and are
designed to cover a pressure range from 125 to
10,000 psi. The temperature range is from
-100 to 275
F (-73 to 135
C).
2.0
DESCRIPTION
See the installation drawing at the front of this manual
for dimensional details of the Series 121A20 and
121A30.
The Series 121A20 and 121A30 have an integral
housing diaphragm machined in stainless steel. The
sensor incorporates ¼ NPT mounting, and terminates
in either a two-pin MIL or integral cable.
Quartz plates are stacked in a thickness compression
mode to produce a relatively high natural frequency.
When pressure is applied to the diaphragm of the
sensor, the quartz element produces a high impedance
voltage signal which the miniature amplifier converts
to a low impedance level voltage (
100
) which can
