# Instrumentation **URL:** https://forumautomation.com/c/interview-questions-and-answers/instrumentation/35.md?page=1 [Latest](https://forumautomation.com/latest.md) · [Categories](https://forumautomation.com/categories.md) · [Tags](https://forumautomation.com/tags.md) **Page:** 2 --- ## [Common Interview Questions: Instrument and Control Engineers](https://forumautomation.com/t/common-interview-questions-instrument-and-control-engineers/139)
**Author:** [@instrumen](https://forumautomation.com/u/instrumen)\ **Replies:** 1\ **Last updated:** [April 15, 2018, 1:47pm UTC](https://forumautomation.com/t/common-interview-questions-instrument-and-control-engineers/139 "2018-04-15T13:47:51Z")
What are the process Variables? Define all the process Variable and state their unit of measurement. ? What are the primary elements used for flow measurement? What are the different types of orifice plates and state th… --- ## [Control valve interview question and answers](https://forumautomation.com/t/control-valve-interview-question-and-answers/2540)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [October 30, 2017, 9:02pm UTC](https://forumautomation.com/t/control-valve-interview-question-and-answers/2540 "2017-10-30T21:02:49Z")
What is a valve? A valve is a device used to control the flow of fluid in a stream. What is a control valve ? A control valve changes the flow rate in the stream as a response to the controller output to change the ma… --- ## [What are the types of Linear displacement transducers?](https://forumautomation.com/t/what-are-the-types-of-linear-displacement-transducers/2351)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [September 27, 2017, 11:44am UTC](https://forumautomation.com/t/what-are-the-types-of-linear-displacement-transducers/2351 "2017-09-27T11:44:05Z")
Resistive potentiometer LVDT Strain gauge Capacitive transducer Variable inductance transducer Piezoelectric transducer Photo electric transducer Hall effect transducer Digital transducer --- ## [What is Benchset and Stroking](https://forumautomation.com/t/what-is-benchset-and-stroking/3052)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [January 29, 2018, 7:25pm UTC](https://forumautomation.com/t/what-is-benchset-and-stroking/3052 "2018-01-29T19:25:47Z")
Benchset: Benchset are the actual pressure ranges for travel of the actuator with no friction. These are the actual maximum and minimum pressures that move the actuator from end to end of its range of operation. This i… --- ## [What are the functions of an Instrument?](https://forumautomation.com/t/what-are-the-functions-of-an-instrument/2972)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 1\ **Last updated:** [February 10, 2018, 9:29am UTC](https://forumautomation.com/t/what-are-the-functions-of-an-instrument/2972 "2018-02-10T09:29:24Z")
The primary function of an instrument is to measure a process variable. While doing so, it performs several functions such as Transmitting,Signaling,Registering,Indicating,Recording. Transmitting – Instrument sends the … --- ## [Level measurement interview questions](https://forumautomation.com/t/level-measurement-interview-questions/3029)
**Author:** [@areejsidhik](https://forumautomation.com/u/areejsidhik)\ **Replies:** 0\ **Last updated:** [January 25, 2018, 12:35pm UTC](https://forumautomation.com/t/level-measurement-interview-questions/3029 "2018-01-25T12:35:50Z")
What is level? The total quantity of substance stored in a tank or vessel. Different types of level measurement instruments used in industries are Gauge glass, pressure gauge -scale graduated in %of level, rope an… --- ## [What is the difference between Direct measurement and Indirect measurement?](https://forumautomation.com/t/what-is-the-difference-between-direct-measurement-and-indirect-measurement/2970)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 14, 2018, 3:44am UTC](https://forumautomation.com/t/what-is-the-difference-between-direct-measurement-and-indirect-measurement/2970 "2018-01-14T03:44:00Z")
Broadly the measurement can be categorized in to two categories Direct measurement 2. Indirect measurement Direct measurement The quantity to be measured is determined directly. Example – Measure distance by scale … --- ## [What is process variable and types of process variables?](https://forumautomation.com/t/what-is-process-variable-and-types-of-process-variables/2818)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [December 14, 2017, 9:51pm UTC](https://forumautomation.com/t/what-is-process-variable-and-types-of-process-variables/2818 "2017-12-14T21:51:22Z")
Instruments are used to monitor and control a process to keep the process within a correct limit. The parameters or quantities that we wish to control at the correct limit are called Process Variables.A variable is some… --- ## [What is a system in Process Control?](https://forumautomation.com/t/what-is-a-system-in-process-control/2742)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [November 28, 2017, 9:40pm UTC](https://forumautomation.com/t/what-is-a-system-in-process-control/2742 "2017-11-28T21:40:56Z")
The controlled system has an input variable and an output variable. Its response is described in terms of the dependence of the output variable on the input variable. These responses between one or several variables can … --- ## [What are the important symbols used in P&ID diagram](https://forumautomation.com/t/what-are-the-important-symbols-used-in-p-id-diagram/2479)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [October 19, 2017, 9:45pm UTC](https://forumautomation.com/t/what-are-the-important-symbols-used-in-p-id-diagram/2479 "2017-10-19T21:45:36Z")
All the devices like transmitters, gauges, and other equipment etc., in a control loop, cannot be picturised to understand the logic. So in a P& id diagram, all the devices are symbolised. Letters and numbers are writt… --- ## [What are the Important interview queations about Control valve?](https://forumautomation.com/t/what-are-the-important-interview-queations-about-control-valve/2403)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [October 7, 2017, 1:28pm UTC](https://forumautomation.com/t/what-are-the-important-interview-queations-about-control-valve/2403 "2017-10-07T13:28:19Z")
What is a control valve? A control valve is a final control element used to control fluid flow by varying the size of fluid passage in response to the signals received from controllers. Control valves are used to contro… --- ## [What is SI unit?](https://forumautomation.com/t/what-is-si-unit/2221)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 1\ **Last updated:** [August 20, 2017, 5:21am UTC](https://forumautomation.com/t/what-is-si-unit/2221 "2017-08-20T05:21:00Z")
What is SI unit? International system of unit (SI) is world’s most used system of measurement. International system of unit (abbreviated SI) is used officially in all countries except USA,Myanmar and Liberia. It has s… --- ## [Instrument and process equipment symbols](https://forumautomation.com/t/instrument-and-process-equipment-symbols/2357)
**Author:** [@sivaranjith](https://forumautomation.com/u/sivaranjith)\ **Replies:** 0\ **Last updated:** [September 28, 2017, 3:13pm UTC](https://forumautomation.com/t/instrument-and-process-equipment-symbols/2357 "2017-09-28T15:13:15Z")
The instrument symbols are as per ISA 5.1 standards, which are applicable in Process Flow Diagrams (PFDs), Process and Instruments, Diagrams (P&IDs), and loop diagrams Line types: Bubble type: Process valve type: … --- ## [How to calculate measurement value from 4-20 ma transmitter output?](https://forumautomation.com/t/how-to-calculate-measurement-value-from-4-20-ma-transmitter-output/2254)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [August 28, 2017, 3:18am UTC](https://forumautomation.com/t/how-to-calculate-measurement-value-from-4-20-ma-transmitter-output/2254 "2017-08-28T03:18:11Z")
The equation to calculate Measurement Value is MV = { \[(TV - TRL) / (TRU - TRL) \] \*(MRU-MRL)} + MRL MV = Measurement Value TRL = Transmitter range low value Eg:4 ma TRU = Transmitter range upper value Eg: 20 ma. … --- ## [What is an Imperial System of UNITS?](https://forumautomation.com/t/what-is-an-imperial-system-of-units/2226)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [August 20, 2017, 6:07pm UTC](https://forumautomation.com/t/what-is-an-imperial-system-of-units/2226 "2017-08-20T18:07:01Z")
Imperial System of UNITS In the imperial system the base quantities are length with units in inches,feet,yards and miles,time with units same as in SI in seconds (s),hours (hr), days (d),weeks and year. Weight with unit… --- ## [Calibration technician interview question?](https://forumautomation.com/t/calibration-technician-interview-question/487)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 1\ **Last updated:** [August 20, 2017, 12:49am UTC](https://forumautomation.com/t/calibration-technician-interview-question/487 "2017-08-20T00:49:59Z")
Top Interview questions : Calibration engineer / Calibration technician 1.What is the purpose of Calibration ? 2.What is traceability ? 3.What is span ? 4.What is range ? 5.Explain about zero suppression / elevation… --- ## [Interview questions - Basic instrumentation](https://forumautomation.com/t/interview-questions-basic-instrumentation/2186)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 1\ **Last updated:** [August 18, 2017, 4:50am UTC](https://forumautomation.com/t/interview-questions-basic-instrumentation/2186 "2017-08-18T04:50:55Z")
Define physical quantity ? Any quantity which can be measured is known as physical quantity. Define Measurend ? A physical quantity which is being measured. Define sensors? Sensors are devices which transform one ph… --- ## [Describe how to install electrical connections in Instrumentation and control loop systems?](https://forumautomation.com/t/describe-how-to-install-electrical-connections-in-instrumentation-and-control-loop-systems/2142)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [July 23, 2017, 11:03pm UTC](https://forumautomation.com/t/describe-how-to-install-electrical-connections-in-instrumentation-and-control-loop-systems/2142 "2017-07-23T23:03:44Z")
Process control depends on the integrity of communication between instruments,information travels through the loop and signals which represents the value of the process variable or the output of the controller. These sig… --- ## [Explain the basics of Open loop and Closed loop control system](https://forumautomation.com/t/explain-the-basics-of-open-loop-and-closed-loop-control-system/2023)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [May 29, 2017, 6:51pm UTC](https://forumautomation.com/t/explain-the-basics-of-open-loop-and-closed-loop-control-system/2023 "2017-05-29T18:51:24Z")
Open Loop Control System. Key point for open loop system is there is no feedback. That means controllers output doesn’t affect its subsequent input. Open loop control system can take input from process as long as con… --- ## [What are the major categories in Temperature measurement techniques?](https://forumautomation.com/t/what-are-the-major-categories-in-temperature-measurement-techniques/1898)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [April 8, 2017, 3:35pm UTC](https://forumautomation.com/t/what-are-the-major-categories-in-temperature-measurement-techniques/1898 "2017-04-08T15:35:01Z")
Temperature Measurement Techniques A wide variety of methods are employed for temperature measurement.There are broadly split into tow groups. Contact Measurement Thermocouples Thermistors Resistance Temperature Detect… --- ## [Basic Instrumentation - Interview Questions and Answers](https://forumautomation.com/t/basic-instrumentation-interview-questions-and-answers/1849)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [March 19, 2017, 5:32pm UTC](https://forumautomation.com/t/basic-instrumentation-interview-questions-and-answers/1849 "2017-03-19T17:32:46Z")
Interview Questions and Answers - Basic Instrumentation What is closed loop ? A Closed control loop exists where a process variable is measured,compared to a setpoint and action is taken to correct any deviation from s… --- ## [Give a brief of Different types of Level Measurement technologies](https://forumautomation.com/t/give-a-brief-of-different-types-of-level-measurement-technologies/1735)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [February 7, 2017, 1:22am UTC](https://forumautomation.com/t/give-a-brief-of-different-types-of-level-measurement-technologies/1735 "2017-02-07T01:22:29Z")
There are many ways to measure level. 1.Differential Pressure / Diaphragm Seal Transmitter measure pressure at the bottom of a tank and converts that pressure to a level reading. 2.Ultrasonic Transmitters Transmitter… --- ## [What is Proportional Integral Derivative Control (PID)?](https://forumautomation.com/t/what-is-proportional-integral-derivative-control-pid/1727)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [February 4, 2017, 5:28pm UTC](https://forumautomation.com/t/what-is-proportional-integral-derivative-control-pid/1727 "2017-02-04T17:28:41Z")
PID - Proportional Integral Derivative Controller The PID function uses system feedback to continuously control a dynamic process. The purpose of PID control is to keep a process running as close as possible to a desir… --- ## [What is the meaning of Explosion proof? What is the difference between explosion proof and intrinsic safety?](https://forumautomation.com/t/what-is-the-meaning-of-explosion-proof-what-is-the-difference-between-explosion-proof-and-intrinsic-safety/1691)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 21, 2017, 5:19pm UTC](https://forumautomation.com/t/what-is-the-meaning-of-explosion-proof-what-is-the-difference-between-explosion-proof-and-intrinsic-safety/1691 "2017-01-21T17:19:16Z")
Explosion Proof- Equipment with an explosion proof classification doesn’t mean the equipment will survive an explosion.Instead it means that the equipment is housed or has an enclosure which prevents an internal spark f… --- ## [What is Intrinsically safe?](https://forumautomation.com/t/what-is-intrinsically-safe/1690)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 21, 2017, 5:04pm UTC](https://forumautomation.com/t/what-is-intrinsically-safe/1690 "2017-01-21T17:04:45Z")
Intrinsically Safe A design technique to limit energy (electrical and/or thermal) below a level required to ignite a specific hazardous atmospheric mixture. Why intrinsic safe is important? This technique is important… --- ## [Definitions of Pressure](https://forumautomation.com/t/definitions-of-pressure/1648)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 11, 2017, 4:35am UTC](https://forumautomation.com/t/definitions-of-pressure/1648 "2017-01-11T04:35:14Z")
Pressure - Normal force per unit area exerted by a fluid on a containing wall with respect to a reference. Absolute Pressure - Normal force per unit with respect to zero absolute pressure. Ambient pressure - The pressu… --- ## [What are the measurement error categories?](https://forumautomation.com/t/what-are-the-measurement-error-categories/1625)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 4, 2017, 6:16am UTC](https://forumautomation.com/t/what-are-the-measurement-error-categories/1625 "2017-01-04T06:16:42Z")
Measurement errors can be categorized in to two 1.Systematic Error A difference from the true value that is usually constant or proportional to the true value. How Systematic error can be eliminated? Identify the sou… --- ## [What are the major terminologies related to Instrument calibration?](https://forumautomation.com/t/what-are-the-major-terminologies-related-to-instrument-calibration/1623)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 4, 2017, 4:50am UTC](https://forumautomation.com/t/what-are-the-major-terminologies-related-to-instrument-calibration/1623 "2017-01-04T04:50:39Z")
Accuracy - The degree of an indicated value to an accepted standard value or true value. Calibration - correcting or determining the error of an existing scale or of evaluating one quantity in terms of reading from ano… --- ## [Fundamentals of Multivariable Measurement?](https://forumautomation.com/t/fundamentals-of-multivariable-measurement/1612)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [January 1, 2017, 5:46pm UTC](https://forumautomation.com/t/fundamentals-of-multivariable-measurement/1612 "2017-01-01T17:46:55Z")
What is Multivariable measurement ? Measuring multiple process variable in one instrument in order to accurately measure volume as well as mass flow through appropriate flow compensation. Flow compensation is divided u… --- ## [What are the two categories of Field Instrument transmitters?](https://forumautomation.com/t/what-are-the-two-categories-of-field-instrument-transmitters/1610)
**Author:** [@denizen](https://forumautomation.com/u/denizen)\ **Replies:** 0\ **Last updated:** [December 31, 2016, 6:02am UTC](https://forumautomation.com/t/what-are-the-two-categories-of-field-instrument-transmitters/1610 "2016-12-31T06:02:20Z")
Instrument transmitters are split in to two broad categories. 1.Loop Powered Instruments. Loop powered instruments are instrument with two wire connection to controller (PLC /DCS/ Stand Alone controller). Two wire con… [Previous page](https://forumautomation.com/c/interview-questions-and-answers/instrumentation/35.md) [Next page](https://forumautomation.com/c/interview-questions-and-answers/instrumentation/35.md?page=2)