Answer / nandan

The principle is that analyzer supplies a negative voltage
to transducer,who converts it into a frequency & sends it
across the probe.Now as the probe comes into the area of
rotor it creates a magnetic field & with it eddy current is
produced on the rotor side.Which changes the amplitude of
the frequency.It induces the voltage & remaining frequency
comes to the transducer through the return way.Transducer
converts it into the voltage .
Now coming back to the question The gap voltage has a
negative relation with the voltage induced i.e. as the gap
increases the induced voltage decreases.So to make it to
into a linear relation ship, negative voltage is supplied.
i.e

Gap Gap voltage
0 mm 0 vtg
1 mm -9 voltage
2 mm 18 voltage
& when the probe is in air it will have no induced voltage
so all -24 voltage without induced voltage will return back.

Answer / jigaranadkat

Because it has PNP transistor inside which requires base
bias of negative (-ve) supply.

Answer / darpan

The principle is that analyzer supplies a negative voltage
to transducer,who converts it into a frequency & sends it
across the probe.Now as the probe comes into the area of
rotor it creates a magnetic field & with it eddy current is
produced on the rotor side.Which changes the amplitude of
the frequency.It induces the voltage & remaining frequency
comes to the transducer through the return way.Transducer
converts it into the voltage .
Now coming back to the question The gap voltage has a
negative relation with the voltage induced i.e. as the gap
increases the induced voltage decreases.So to make it to
into a linear relation ship, negative voltage is supplied.
i.e

Gap Gap voltage
0 mm 0 vtg
1 mm -9 voltage
2 mm 18 voltage
& when the probe is in air it will have no induced voltage
so all -24 voltage without induced voltage will return bac

Answer / mohammed abbas

Because it is NPN tansistor during the initail days when
this was inveted by bently the cost of NPN transiator was
less. then they started use NPN transiator for the
vibration propbe, due to this we will give negative 24vdc
supply

Answer / shankar rao

negative feed back required.

Answer / sai kiran.c

does really negative voltage exists......???

i have used level transmitter in starch cooking preparation tank. tank total height 2mtr.sometime LT display shows some error value when tank is fully empty and diaphragm side i already checked okay no problem in diaphragm area. field cable checked 24volt and mA shows correct value while tank empty mA is 4mA. 4mA i needed that 0% but display showing 10% or 15% percentage values are varying continously please give any good solution for me.....

0 Answers  

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