Sunday, June 5, 2011

INSTRUMENT QUESTIONAIRE

Name three devices for measuring:
FLOW: Rotameter, Turbine meter, Vortex meter.
LEVEL: Level Troll, Displacer, Delta P Transmitter.
TEMPERATURE: Thermocouple, RTD, Thermistor.
What are these?
·         TYPE J THERMOCOUPLE: Iron Constantan.
·         TYPES THERMOCOUPLE: J, T, K.
·         TYPE T : -200 ~ 400ºC.
·         PT 100 : RTD
What is PT 100 in RTD?
100 Ώ = 0ºC. And 138.5 Ώ = 100ºC.
4. What is burn out protection?
It is protection component from short circuit.
What is thermo well?
It is for protection temperature sensor or element sensor, as like T/C or RTD.
Capillary type temperature instruments come under which category of measurement?
Is Temperature measurement (gas actuated).
What are the different types of flow measuring primary devices?
· Orifice plate.
· Venture tube.
· Anubar.
What is intrinsic safety?
Involves making electrical equipment safe for hazardous areas by limiting the available energy to a level too low for flammable mixture to ignite.
How is intrinsic safety achieved?
By installed safety barriers.
What is division II area?
Normally non hazardous area but my become hazardous under abnormal circumstances such as equipment failure.
What are the various types of fire and gas detectors used in industry?
Fire : UV (ultra violet) / IR (infra red).
Gas : Catalityc, IR ( Infra red ).
What is the unit used to measure level of flammable gas in a area?
Percentage.
Unit of measurement for toxic gases?
PPM (part per million).
Why valve positioner is used in control valves?
a. For positioning action of control valves
b. For making fast action of control valves
c. To change direction control valve, such as reverse or direct.
d. For making linier action of control valves
What is a fast loop in an analyzer sampling system?
For fasting process the sample catching comes in to the Gas Chromatograph (GC).
What are different types of detectors used in gas chromatograph?
T C D : Thermal Conductivity detector
F I D : Flame Ionization Detector
What does :
i. One bar equal in PSI?
14.2 PSI
ii. One PSI equal in inches of water?
0,254? H20
iii. PSI stand for?
Pound per Squares Inch
When referring to 3 type controllers, what do letters P.I.D stand for?
P = Proportional (Gain). Reduce oscillation.
I = Integral (Reset). Reduce deviation.
D = Derivative (used in the temperature controller, function is reduced the time lag).
What is the standard out put range of a :
1. PNEUMATIC TRANSMITTER : 3 ~ 15 PSI or 0.2 ~ 1 Kg/cm².
2. ELECTRONIC TRANSMITTER : 4 ~ 20 mA or 1 ~ 5 Vdc.
Write OHMS law?
· R = E / I
What is closed loop?
1. Output controlled by feed back.
2. Is a system in which all control system where controlled by instrumentation.
What are the different types of controls commonly used?
3. Process Control.
4. Sequential Control.
23. Give an example of cascade control?
a. Level and Flow.
b. Level and Temperature.
What is feed forward control?
5. Input is equal with output and no need feed back for correction.
6. Is a system in which balance between supply and demand is achieved by measuring load and demand potential and then use this information to govern supply.
Example: TEMPERATURE RECORDER. Or HEAT EXCHANGER SYSTEM.
25. How does displacement level instrument work?
· Base on Archimedes principle that is a body immersed in a liquid will be buoyancy forces equal to the liquid displaced.
26. What is the important component of level troll?
· Floater.
· Displacer.
27. What are the different types of element used for pressure measurement?
· Bourdon Tube.
· Bellows.
28. What is LVDT and what is used for?
· Linear Variable Differential Transformer.
· It is used for Level Measurement.
29. What is GC? Where it is used?
· GC = Gas Chromatograph.
· There are used in the gas industry as like LNG, GTL or LPG plant.
30. What are the major components of a GC?
· Column.
· Heater.
· Valve.
· Detector.
31. What are the major components of a Turbine?
· Rotor.
· Governor.
· Impeller.
32. What is the fuel valve in a turbine called?
· TTV = trip Trotel Valve.
33. What are the major controls in a Gas Turbine?
· Ignition Control.
· Temperature Control.
34. What are two shaft machines?
35. How is the exhaust temperature in turbine measured?
· Used RTD or Thermocouple.
36. What are the types of level instrumentation used for closed tank level measurement?
· Differential Pressure.
· Displacer.
· Capacitance.
· Conductance.
· Ultrasonic.
37. What are proximity transducer system and its components?
· Used EDDY CURRENT principle to measure the distance from the probe to the surface of the shaft.
· Components are: - PROXIMITOR.
- PROBE.
- EXTENSION CABLE.
38. What does proximity do and its voltage level?
· This accomplished by the generation of small radio frequency (RF) in the proximitor, RF signal surrounding the probe tip (coil) is used to measure the probe tip to target average (DC) gap voltage utilizing the eddy current.
· Voltage level normally is -18 VDC or -24 VDC, depend on the proximitor type.
39. What is gap voltage?
· It is distance from the probe tip to the target surface, measure gap of target.
40. What is this gate called?
· NAND GATE = NOR AND GATE.
· XOR GATE = EXCLUSIVE OR GATE
41. What neither is the truth table of NOR gate?
A
B
C
0
0
1
0
1
0
0
0
0
1
1
0

42. In electronics, what do these stands for?
· BCD = BINARY CODE DECIMAL.
· DAC = DIGITAL ANALOGUE CONVERTER.
· ADC = ANALOGUE DIGITAL CONVERTER.
· PCM = PULSE MODE MODULATION.
43. SCADA = Supervisory Control And Data Acquisition.
44. RTU = Remote Telemetry Unit.
45. MODEM= Modular Demodular.
46. DAM = Digital Analogue Module.
47. Major component of SCADA are:
· RTU, DCS, ANALYZERS, RADIO LINK, FIBRE OPTIC LINK, OPERATING INTERFACE, and EVENT LOGGER.
What is thermocouple?
· A pair of different conductor joined so as to produce a thermoelectric effect (in mV) depend on temperature.
How many type cage plug valves?
· a. Linear.
· b. Quick opening.
· c. Equal percentage.
How many type control valves?
· Butterfly.
· Globe valve.
· Ball valve.
What are cavitations?
It is a bubbling happens on the valve and can make damage.
Please explain about 2 of 3 with drawing?
Please explain about interlock system?

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