WIKA 892.34.1998 - Handbuch (Seite 11)

- page 14 - - Seite 11 -
Deutsch
B e t r i e b s a n l e i t u n g f ü r D r u c k m e s s g e r ä t e m i t F e r n g e b e r O p e r a t i n g I n s t r u c t i o n s f o r P r e s s u r e T r a n s m i t t e r s
Table of contents
page
1 Operating principle 14
2 Installation instructions 15
3 Mounting and operation 16
4 Arrangements for pressure measurement 16
5 Wiring details 17
6 - class version 17
7 Technical data 18
8 Service and maintenance 19
9 Special features for differential pressure transmitters
with mounted valve manifold
20
10 Storage 21
11 Trouble shooting 21
12 Measures to be taken by customer for returns and repairs 22
13 Disposal/end of service life
22
Enclosure 1: EC-type examination certificate Model 892.34 23-24
1 Operating principle
Pressure transmitters for differential pressure mainly consist of the functional groups:
• mechanical measuring system with an elastic pressure element
• Hall-effect sensor with amplifier
• cover with the electronical connections
Under the influence of pressure the elastic zone of the measuring element is deformed
and this movement is used to alter a magnetic field.
This chain is converted without contact by a magnetic field-dependent sensor (hall-sensor)
via an amplifier into an electric output signal. This output signal is set at the factory as
measuring range (for example 4 ... 20 mA) and corresponds with the measurement span
on the respective pressure range.
The standard 4 ... 20 mA current signals in 2-wire system or 0 ... 20 mA in 3-wire system
are generated by the integrated amplifier.
The intrinsically safe version, Model 892.34, has to be used in explosion hazardous
areas.
The EC-Type Examination Certificate of the DMT (Deutsche Montan Technologie GmbH)
for intrinsically safe instruments in ignition protection Class
II 2G EEx ia IIC T6 and
I M2 EEx ia I is provided for Model 892.34. Due to the standard 4 ... 20 mA output signal
these gauges can be used in all industries.