Answer / naveed iqbal

actually in proximaty probes inside used PNP tanasistor.so
transistor baising supply need - dc voltage.

Answer / chandrakant sahu

There is PNP type transistor used in ocsilator and also ti keep minimum interference negative voltage is suitable for this

Answer / waleedmahmoud

The basic reason is that the power supply is -24 VDC. So
since the supply voltage is negative the output voltage
will be as well.

IRD at one time made prox probes with a positive supply and
as a result a positive output.

Way back in the 50's uncle Don Bently made a design
decision to use a negative supply voltage (back then it
was -18 VDC rather than -24 VDc in the modern device) in
his circuit. This decision has stuck and is now even
included in the API standards

Positive are also there for example.

Metrix 5465F is -ve gap voltage

Metrix 5465E is +ve gap volatge

It does not make much of a difference wether you use
positive or negetive voltages. It is -ve because Bently
started with the design of -ve and now we stick to -ve.

Answer / md. rizwan

Because we measure the negative voltage in vibration system.

How many ohms are required for proper earthing?

0 Answers  

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Questions on flow meters,few questions on HART protocol,

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what is difference between accelerometer vibration sensor and proximity vibration sensor

3 Answers  

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any body please send me the old question papers of ongc test.

0 Answers   NTPC,

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why use on -off control valve in glove valve

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as an instrumentation engineer which are the things we have to know / or we must have idea about that....

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HOW TO CHECK THERMOCOUPLE AND RTD & WHAT IS THE DIFFERENCE BETWEEN THERMOCOUPLE AND RTD

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can we create an interrupt in plc through scada?

0 Answers   Glensol, TATA,

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can you give some devices that measure directly the mass flow rate.

1 Answers   Takreer,

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why r using 250 resistances

6 Answers   Sabic, Samsung,

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What is the use of control cable?

0 Answers  

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