2 | Product and functional description
FISCHER Mess- und Regeltechnik GmbH
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BA_EN_DE43
2.3 Function diagram
DIP
µC
D
A
D
A
E1
E2
E3
E4
BUS
POWER
+
+
P1
P2
2
Input 1
Input 2
Input 3
Input 4
1
Modbus IN
Modbus OUT
1
2
3
4
5
6
7
Fig. 6:
Function diagram
1
Sensor element
2
Micro-controller
3
AD converter
4
Digital inputs
5
Modbus interface
6
Power Supply
7
Modbus configuration
2.4 Design and mode of operation
The basis of the DE43 transmitter comprises two piezoresistive sensor ele-
ments.
The pressure that is to be measured acts upon a silicone membrane that is
equipped with a resistor bridge. The acting pressure causes the membrane to
move and therefore a change in resistance. The bridge signal is analysed by
the integrated electronics and converted to a pressure value.
The DE43 transmitter communicates with an overriding control system via an
RS 485 interface and a Modbus RTU protocol. The currently measured value is
forwarded by the overriding control system on request.
The device also has a connecting slot for two or four proximity switches whose
signals can also be queried through the Modbus by the overriding control sys-
tem.
2.5 Intended use
The digital 2-channel transmitter DE43 is suitable for measuring pressure, un-
der-pressure, and differential pressure in neutral gaseous media. The measured
value is transferred to an overriding control system via an RS 485 interface with
a Modbus RTU protocol.
Optionally, the device can monitor up to four external potential-free contacts,
and send their switching status to the overriding control system.
