Process Measurements and Control ELEX 2830

Upon successful completion of the course, the student will be able to:

INTRODUCTION TO INSTRUMENTATION

Identify the symbols, terminology and characteristics of process control.

• Appreciate the need for automatic control systems.
• Describe the major elements required for a feedback control system.
• Differentiate between open and closed loop systems.
• Define terms used in the instrumentation and control field.
• Interpret and apply the ISA symbology used to document simple process measurement and control systems.

THE ROLE OF MEASUREMENT SYSTEMS

Calibrate a measurement system and produce a calibration report.

• Define primary element, transducer, transmitter, span, gain, range and zero.
• Derive a static operation equation for a given measurement system.
• Identify the need for calibration.
• Plot the ideal and actual static responses for a measurement system.
• Distinguish between the different types of error(s) used to describe the accuracy of an instrument.
• Apply standard ISA symbology to transducers commonly used in process automation applications.

PRESSURE MEASUREMENT

Assess the suitability of a pressure measuring instrument for a specific application.

• Define pressure and the units of pressure.
• Describe pressure standards.
• Apply the equations derived for standard manometer configurations to simple problems.
• Describe the common mechanical pressure elements.
• Describe the common electrical pressure transducers.
• Calibrate an industrial differential pressure transmitter.
• Recognize how pressure measurement can be used to determine liquid level and density.

STRAIN MEASUREMENT

Assess the characteristics and limitations of strain gauges to measure strain.

• Define units of stress and strain.
• Define Young’s modulus of elasticity.
• Define Poisson’s ratio.
• Perform simple calculations to predict stress and strain.
• Define gauge factor.
• Calculate strain in a cantilever beam application.
• Calculate the output voltage of a Wheatstone quarter and half bridge circuit.

LEVEL MEASUREMENT

Assess the suitability of a level measuring system for a specific application.

• Distinguish between different level measurement techniques (i.e. direct or inferential).
• Describe common direct level measurement techniques.
• Describe common inferential level measurement techniques.
• Calculate the level in an open tank.
• Calculate the level in a closed tank.
• Describe the operation of extended and remote diaphragms, bubblers, and purge systems.

TEMPERATURE MEASUREMENT

Assess the suitability of a temperature measuring instrument for a specific application.

• Define temperature and the units of temperature.
• Review the principles of heat transfer.
• Plot the response of a first order temperature system to step and ramp changes.
• Describe temperature measuring systems using the principle of volumetric expansion.
• Describe the Seebeck effect and explain how it relates to thermocouples.
• Define the thermocouple laws of intermediate metals, intermediate temperatures and homogenous materials.
• Calculate the temperature using standard thermocouple tables.
• Describe other types of temperature instruments viz. resistance temperature detectors and thermistors.

CLOSED LOOP CONTROL

Appreciate the characteristics and limitations of basic closed loop control strategies.

• Identify and describe the limitations of closed loop control. Describe the lags primarily responsible for process dynamics.
• Describe the two position (On/Off) closed loop control and assess its effectiveness as a control strategy.
• Explain the proportional control strategy and identify its limitations.
• Define integral and derivative control strategies and describe how these strategies are able to improve closed loop control.
• Investigate proportional, integral and derivative control and appreciate the advantages and limitations of each mode of control.

Effective as of Fall 2016