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AMP.
Figure l-l.
Block Diagram
The basic operation of the system is as follows:
The frequency signal from the flowmeter is connected to the FTB500 with
a twisted pair shielded cable. The signal enters through the SENSITIVITY
control which is used to reject unwanted noise by raising the trigger
threshold above the background noise present.
The low level flowmeter signal is then passed through a special condition-
ing chain where it is filtered, amplified, and shaped into a train of digital
pulses whose frequency is non-linearly related to the volume flow rate.
The digital pulse train is then passed through the linearizer where the off-
set frequency signal is injected into it. For flow rates within the range of the
meter, the linearizer output will be linearly related to the volumetric flow rate
In addition, this circuitry drives the
' low flow ' out of range indicator.
2
pcA_,,B
CONDITIONER
TURBINE FLOWMETER=
MAIN CHASSIS
FREQ. TO
CONVERTER
-
-
CAPACITOR COUPLED
ANALOG
OUTPUT
OUTPUT
FTBBOO SIGNAL
1.3
THEORY OF OPERATION
A simplified block diagram of the FTB500 Mini Flow Signal Conditioner is
shown in Figure 1-I.
SENSITIVITY
+v
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