Instrumentation. Test 4 – Online Maritime Tests

This is a simplified block diagram of a dc generator and its voltage regulator. Find the value of the feedback constant H if the reference VR is a 45-Volt battery and the terminal voltage Vt is to be 250 Volt.

H = - 11.1
H = 5.5
H = 0.55
H = - 0.178

You have to choose one of the following instruments for measuring pressure in an air bottle in measuring range 0 - 35 BAR. Which instrument will you install?

Bourdon Tube manometer
U-type H2O manometer
Bellow type manometer
U-type Hg manometer

Thermocouples are often used for measuring temperatures. Which of the following descriptions are valid for a thermocouple?

A resistance device that exhibits a positive coefficient of resistance with temperature.
A quartz crystal that changes its resonant frequency with temperature.
A semi-conductor device that exhibits a negative coefficient of resistance with temperature.
A junction between two dissimilar metals generates a small voltage.

What is an I/P Transducer?

A transducer that converts a known electric current to a pressure proportional to the current.
A transducer that converts a pressure to a proportional electric signal.
A transducer that is inverting a pressure signal.
A transducer that increase a pressure signal which is too low to give the desired effect.

When you are calibrating an instrument what is the most common first step in the procedure (consult the manual)

Adjustment of range
Adjustment of span
Adjustment of Zero-point and span
Adjustment of linearity

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