Sample Instrumentation Interview Question & Answers That can be asked in M/s Saudi Aramco

In my Previous video I discussed regarding what is Proximity Sensor, Types of Proximity sensors, link for this is given in the description below

In todays video I am gonna discuss Sample Instrumentation Interview Question and Answers that can be asked by M/s Saudi Aramco
Q: What is the difference between PLC & DCS?
.Q: Why we need 250Ohms Resistor during the calibration of HART Instruments?
A: If you add 250 ohms resistance in the loop you will get some DC voltage drop but also across the resistor you will get the HART signal. To operate a Digital signal we need 1-5Vdc for this we are using 250 Ohms Resistor.
Q: What is Dry Leg Calibration and Wet Leg Calibration?
A: Dry leg Calibration is used only for level measurement in a closed tank with liquids at ambient temperature. Wet leg calibration method is required for level measurement in a closed tank with hot and intensely cold liquids. * Vent the L.P. side to atmosphere.
Q: Why we use 4 - 20 mA instead of using 0 - 20mA?
A: It’s easier to detect a broken wire, because the current will drop and the system can easily identify the error.
Q: What is the difference between deflecting and null type instrument?
A: The Deflection type instruments are less accurate as their calibration depends on the instrument constants, these are better suited to measure transient quantities because changes in a quantity can be better followed by a pre-calibrated pointer. On the other hand, the accuracy of Null type instrument is far higher because of calibration done against a pre-calibrated system; but these are much more suited to measure stable quantities because of the problem of manual control involved in most of them.
Q: what is bevel? why bevel required in orifice plate?
A: Orifice plates which are used in flow measurement are mostly concentric “square-edge” type. The bore of the orifice is not constant when one moves from the upstream side to the downstream side along the cross section. The bore size is constant for a few mm only and then expands till it reaches the downstream face. This inclined cut is called the bevel in an orifice.
The main reason to have a bevel in the orifice is to avoid turbulence thereby providing more accuracy to the measurement.
Q: What is pyrometer? which purpose it has to be used?
A: A Pyrometer is a type of remote-sensing thermometer used to measure the temperature of a surface
Q: What is cold loop checking and Hot loop Checking?
A: Cold loop checking is about to identify and ensure the not powered / not connected loop.Hot loop checking is done once the instruments is connected with.
Q: What are the parts of coaxial cables?
A: Center Core, Dielectric Insulator, Metallic Shield, Plastic Jacket
Q: What is Junction Box?
A: An earthed enclosure within which wires or cables can be safely connected
Q: What is instrumentation?
A: It is a branch of science which deals with measurement and control of process variables such as pressure, flow, temperature, level and etc
Q: What kinds of materials being used for impulse tubing pressure leak testing?
A: Nitrogen and Water
Q: What are the Kinds of Metering Instrument?
A: The following are the different kinds of Metering Instruments,
Conventional electronic and pneumatic transmitter, Transducers, Indicators, Pressure Gage, Thermocouples, Resistance Temperature detectors, Level Transmitter, Instruments air line pressure gage, Turbine positive displacement and magnetic flow meters, Pilot Tube annular flow meters
Temperature gage
Q: What are the tasks to be performed during instrument loop checking?
A: The following are the tasks to be performed during Instrument Loop Checking,
Conducted as per cable package and markings, Tagging and Wire color coding. Testing to be conducted or using test equipment or hand tools continuity test and referenced loop package documents
Considering to identify the Instruments loop (either Closed Loop or Open Loop)
Obtain Documents pertaining to the process loop in order to understand All devices and their intended functions
Inspect the loop components through visual observation in order to ensure that the components are correctly installed
The prepared approved Instrument loop package or folder shall be always implemented

[gameprabusinghjosephselvin]

Really useful video awesome thanks sir and continue videos needs.

[prabuganeshtharmaraj]

Very helpful please upload more q&a instrument maintenance Technician

[wilcc]

very good instructive video...thanks a lot!!

[gnanaduraiinbaraj]

Thank you very much, it is very useful to me.🙏

[mannuemotional]

Plzz make video for maintenance instrument technician important question.