Engineering, Control Systems. Test 56

What do the letters 'PT' shown in this instrument symbol (drawn on the bottom line) indicate if found in an automation schematic drawing ?

First letter: Monitoring, Second letter: Working function.
First letter: Measuring, Second letter: Steering.
First letter: Monitoring, Second letter: Controlling.
First letter: Measuring function, Second letter: Working function.

For what purpose is spring ball adjustment screw item No 2 fitted on the spring blade of this pneumatic amplifier ?

To adjust the valve stem distance.
To adjust the spring blade and output pressure Pu initially.
To control the nozzle back pressure.
To control the rate of amplification response.

Comparing this pneumatic control unit with the equivalent electrical amplifier. What takes the place of the air restrictor passage used in the pneumatic nozzle/flapper unit in the electrical equivalent ?

Resistor R2.
Voltage U1.
Voltage U2.
Resistor R1.

What does a broken or dotted line represent in automation schematic diagrams ? (the second line from top shown here)

A pneumatic line.
A steering line.
An instrument line.
A measuring line.

How is stern tube wear down measured when in dry-dock?

By a poker gauge, inserted in the plugm above the stern tube boss.
By blade feelers inserted in the after seal.
By blade feelers inserted in the forward bush from the engine room.
By measuring the lift on the shaft.

The LSU's (Local Scanning Units) have to measure temperature, pressure, flow, level, RPM, torque, horsepower, circuit and salinity and do so via analog and digital tranducers. What is a digital transducer ?

A digital transducer gives a continue signal , example 0 - 100 mV.
A digital transducer is an electronic instrument opposed to an Analog tranducer which is pneumatic operated 3 to 15 psi.
A digital transducer works on AC voltage.
A Digital Transducer gives a direct ' on ' or ' off ' signal and involve logic transducers.

Review Answers