Cảm Biến Điện Dung Và Nam Châm - P2
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (605.83 KB, 13 trang )
Capacitive/Magnetic
Capacitive/Magnetic
Sensors
Sensors
PEPPERL+FUCHS
©Pepperl+Fuchs Kolleg GmbH, Page 1
Introduction
to
capacitive
and
magnetic
Sensors
Capacitive/Magnetic
Capacitive/Magnetic
Sensors
Sensors
PEPPERL+FUCHS
©Pepperl+Fuchs Kolleg GmbH, Page 2
Capacitive Sensor
Sensor electrode
Shielding
Printing board
Housing
Potentiometer
Capacitive/Magnetic
Capacitive/Magnetic
Sensors
Sensors
PEPPERL+FUCHS
©Pepperl+Fuchs Kolleg GmbH, Page 3
Physical Basics
s
Sensor electrode
Shield
Target
C = f(ε
0
, ε
r
, A, s
-1
)
Capacitive/Magnetic
Capacitive/Magnetic
Sensors
Sensors
PEPPERL+FUCHS
©Pepperl+Fuchs Kolleg GmbH, Page 4
Types of Influences 1
Conductive, earthed target Conductive, insulated target
In both applications an inductive sensor should be used!
Capacitive/Magnetic
Capacitive/Magnetic
Sensors
Sensors
PEPPERL+FUCHS
©Pepperl+Fuchs Kolleg GmbH, Page 5
Types of influences 2
Non conductive target
☞
This is the typical application for capacitive sensors
☞
The switching distance depends on the relative permitivity
ε
r
(reduction factor)
ε
r
ε
r
