Design - ABB FV4000 Operating Instruction

2.2

Design

Fig. 10
1 Sensor
2 Vibration sensor
3 Flow sensor
4 Amplifier with automatic gain control
5 Gain control
6 Amplifier
7 A/D-D/A converter
1) FIR = Finite Impulse Response
The flow and vibration piezo elements from the sensor deliver signals which are forwarded to
the analog-to-digital converter via an amplifier. A gain control mechanism in the DSP controls
gain via the D/A converter. Gain control is used to adapt the necessary signal gain dynamically.
The filter algorithm in the DSP evaluates the signals, picks up the flow signal and sends this
frequency to the CPU for conversion into flow units. This data is then shown on the display and
transmitted on the current and switching outputs or via fieldbus communication.
D184B097U02
3 6
2 5
1 4
FV4000 / FS4000
A
9
D
x
A
-1
Z
D
7 8
8 DSP
1)
9 FIR filter algorithm and gain control
10 Serial interface
11 Frequency
12 CPU
13 Current output
14 Switching output
Design and function
11 14
x
12
+
10 13
G00701
21