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......???

Yokogawa mass flow meter shows negative reading...what r the main causes for this problem?...

3 Answers   IOCL,

how to convert MA in to measuring values..and how mwasuring values into MA ?..plz ansr.i have intervw

0 Answers  

if change the pid in D value so what action.

2 Answers   Siemens,

How ejector(or)evactor air pump is working in thermal power plant?

0 Answers  

Explain how thw analog to digital converter works with the circuit diagram

0 Answers  

What is difference between converter & transducers?

4 Answers  

what sud u do if u dont get feedback from control valve?

1 Answers   Siemens,

which is the best type to measure level of a Tank(water). Displacer or Differential Pressure method?

2 Answers  

what is the procedure of O2 analyser calibration?

3 Answers   Thermax,

procedure to commission a drum level transmitter

1 Answers  

TEMPERATURE VARIATION FOR FREQUENTLY.

0 Answers   TVS,

HELLO FRENDS ,, I M IN THE MIDST OF TROUBLE .. JUST LITTLE HELP ME... SUPPOSE ,, I HAVE A CLOSE VESSELE TANK ( HEXANE MEDIA ) ,, I M USING ROSEMOUNT 2051 DPT FOR LEVEL APPLICATION .. ITS CALIBRATE RANGE IS.. . 0 TO 950 MMH20 ..I DID CALIBRATED DPT WITHOUT REMOVING IMPULSE LINE OF HIGH AND LOW TAPPING.. & WITHOUT DISTURB 3 WAY MANIFOLD..!!! BUT ,,, DURING CALIBRATION I SELECT RANGE BY HART LRV IS 900 MMH20 & URV IS 1300 MMH20 ,, BUT ,TANK LEVEL SOMETIMES 100 % AT 1100 MMH20 , SOMETIMES 1300 MMH20 ..IN THIS CONDITION .. WHOLE LOOP FAILED ,, MAIN THING IS THAT ,, HOW TO CUSTOME RANGE SELECT ?? AND IF I USED RANGE OVER THE ORIGINAL CALIBRATE RANGE ,,,THEN WHAT ERROR WILL BE COME ??? HOW TO ZERO CALIBRATION OF DPT... HOW TO ZERO TRIM BY MANIFOLD ?? AND FOR TANK LEVEL PURPOSE ... WHICH UNIT I CAN USE ??? IS THERE ANY CALCULATION OR CALIBRATION .. IF YEH .. THEN PLZ JUST GIVE ME CALIBRATION STEPS FOR DPT.. THANKS YOURSSSSSSS

1 Answers   Torrent Pharma,