(SEM III) THEORY EXAMINATION 2024-25 SENSOR & INSTRUMENTATION

SENSOR & INSTRUMENTATION – Full Paper 

TIME: 3 Hours | MAX MARKS: 70

This examination evaluates a student’s understanding of sensors, transducers, measurement systems, data acquisition, smart instrumentation, and modern embedded measurement technologies. The paper includes conceptual questions, applied explanations, block diagrams, and analytical reasoning related to sensing principles used in engineering systems.

The question paper is divided into three major sections to test knowledge clarity, analytical skills, and system-level interpretation.

SECTION A – Short Conceptual Questions (14 Marks)

This section contains seven brief questions, each designed to check the student’s basic understanding of fundamental sensor and instrumentation concepts.

Key Concepts Covered

• Transducers

Understanding devices that convert physical quantities (force, temperature, pressure, displacement) into electrical signals.

• Types of Displacement Sensors

Knowledge of resistive, capacitive, inductive or optical-based displacement sensing techniques.

• Thermal Imaging

Use of infrared radiation detection for temperature distribution analysis, industrial diagnostics, medical imaging, and surveillance.

• Proximity Sensors

Capacitive, inductive, ultrasonic, or optical sensors used to detect object presence without physical contact.

• Programming Loops

Understanding For, While, Sequence loops used in automation, embedded systems, and virtual instrumentation.

• ADC (Analog-to-Digital Converter)

Its role in converting analog sensor output into digital data for controllers and processors.

• Self-Calibration

How smart sensors auto-adjust to improve accuracy, correct drift, and maintain reliability without manual recalibration.

This section measures clarity, accuracy, and concept-level understanding.

SECTION B – Applied & Analytical Questions (21 Marks)

Students must attempt any three questions. These require explanatory diagrams, working principles, and application-based reasoning.

Topics Included

• Potentiometer as a Displacement Sensor

Explaining resistive track movement, linear/angular displacement detection, and common industrial uses.

• Thermistor Functioning & Use

Temperature-dependent resistance variation, negative temperature coefficient behavior, and thermal sensing applications.

• Graphical Programming Structures

Case selectors, Sequence frames, Formula nodes used in LabVIEW or graphical system design.

• Data Acquisition System Block Diagram

Signal conditioning → ADC → Controller → Memory/Output stages.

• Intelligent Sensors

Integration of sensing element + signal processor + microcontroller + communication interface.

This section evaluates understanding, analysis, and the ability to explain sensing systems logically.

SECTION C – Long Descriptive Questions (21 Marks)

Students must attempt one question from each subsection (3–7). These questions involve in-depth explanations, working mechanisms, and diagram-supported reasoning.

C1: Mechanical / Electrical Sensors

Option A – Strain Gauge Working

Explaining resistance change due to strain, Wheatstone bridge interface, and force measurement applications.

Option B – Diaphragm-based LVDT for Pressure

Pressure deflection of diaphragm → displacement of LVDT core → converted into voltage.

C2: Position & Flow Measurement

Option A – Hall Effect Sensor for Position

Magnetic field interaction generating voltage proportional to position or rotation.

Option B – Ultrasonic & Laser Flow Sensors

Time-of-flight principle (ultrasonic) and Doppler/beam interruption methods (laser-based flow).

C3: Virtual vs Traditional Instrumentation

Option A – Virtual Instrumentation

Software-based measurement systems, flexibility, data logging, remote access, and cost advantages.

Option B – Comparison with Traditional Instruments

Hardware-only instruments vs PC-based, reconfigurable measurement systems.

C4: DAC Systems & Communication

Option A – R-2R Ladder DAC

Binary-weighted resistor network, equal resistance ratios, stability, and advantages over weighted resistor DAC.

Option B – Data Sockets

Network communication objects enabling real-time data exchange, remote monitoring, and distributed measurement systems.

C5: Smart Sensor Characteristics & Components

Option A – Components of a Smart Sensor

Sensing element, ADC, microcontroller, memory, calibration module, communication interface.

Option B – Characteristics of Smart Sensors

Self-calibration, self-testing, self-communication, diagnostics, and automatic error reporting.

Purpose of the Examination

The BOE305 Sensor & Instrumentation exam ensures that students can:

Understand fundamental sensing principles

Explain the working and application of major sensors

Interpret block diagrams and signal flow

Analyze temperature, displacement, pressure, and flow measurement systems

Use concepts of data acquisition and virtual instrumentation

Understand smart sensors and modern embedded measurement technologies

Solve real-world engineering measurement problems

The paper bridges classical measurement techniques with modern intelligent sensing technologies.