Bronkhorst®
Instruction Manual EL-PRESS™
9.17.101I
8
EL-PRESS™
series instruments are typically equipped with a diaphragm type piezo-resistive pressure sensor and a digital
printed circuit board and offer high accuracy, stability and reliability. The basic digital printed circuit board contains all of
the general functions needed for measurement and control. In addition to the standard RS232 output, all models also offer
analog I/O signals. As an option, an integrated interface board enables operation via DeviceNet™, PROFIBUS DP, PROFINET,
Modbus or FLOW-BUS.
The pressure sensor is a piezo-resistive bridge on the surface of a silicon chip,
with a pressure diaphragm, whose thickness determines the pressure range.
When a pressure acts on this chip, the diaphragm flexes, and the resistor values
of the bridge alter in proportion to the pressure. The measuring cell is separated
from the external pressure by a thin, sensitive stainless steel diaphragm, and the
sealed off cavity between diaphragm and cell is filled with oil.
The standard oil filling of the sensor is flammable, Bronkhorst advises to take adequate security precautions when oxygen
or any other explosive fluid is used.
The
EL-PRESS™
product range contains 4 instrument types, characterized by specific pressure measurement or control
methods. The instrument type is specified at ordering time, and can be retrieved from the
on the serial number
label.
1.3.1
Pressure meter (P-500 series)
A pressure meter can be used to measure
the pressure in a fluid line.
A differential pressure meter (P-506) is a
special type of pressure meter, that can
measure the pressure difference (
D
P)
between two separate fluid lines.
