Data Transmission

Table of Contents

Chapter 1: Process Data Transmission Methods

Topics: Data handling; Local and remote indicators; Mechanical, hydraulic, pneumatic, electronic, optical, and telemetric data transmission

Learning Objectives:

• Describe the differences between data transmission in open- and closed-loop systems and with local and remote indicators.
• Discuss the differences among analog, digital, and discrete control.
• Discuss the use of intrinsically safe and explosion-proof equipment.
• List the advantages and disadvantages of mechanical, hydraulic, and pneumatic data transmission.
• Compare voltage-loop and current-loop transmission for analog data and explain the importance of resolution for digital data transmission.
• List the advantages and disadvantages of optical and telemetric data transmission.

Chapter 2: Electrical Data Transmission

Topics: Analog and digital data; Electronic PV indicators; Signal conditioning and conversion; Compensation; Span and zero adjustment; Linearization

Learning Objectives:

• Compare analog and digital data representation.
• Discuss uses for bar graph displays, CRT displays, recorders, and data loggers.
• Describe the characteristics of the electrical output signals from analog sensors and transducers, using a strain gauge as an example.
• Discuss the significance of the common-mode rejection ratio in signal conditioning.
• Describe the processes of signal conversion, compensation, zero and span adjustment, linearization, and conversion to engineering units.

Chapter 3: Digital Data Transmission

Topics: Number systems; Data formats; ASCII; Error correction; Analog-to-digital conversion; Distributed process control; Parallel and serial data transmission

Learning Objectives:

• Discuss the differences between analog and digital data forms.
• Discuss several reasons for using digital data.
• Describe methods used to interface process control data signals to a communications network.
• Explain how analog data are converted to digital form for transmission and display.
• Discuss the differences between parallel and serial data transmission systems.

Chapter 4: Optical Data Transmission

Topics: Fiber optic cable, connection, and transmission advantages; Optical propagation; Installation of cables; Light sources; Detectors; Standards

Learning Objectives:

• Name the basic elements in a data transmission system based on light energy.
• Explain how optoisolators work and why they are used.
• Describe the advantages and disadvantages of optical data transmission.
• Explain how light rays are propagated down glass fibers.
• Discuss connection and installation methods for fiber optic cables.
• Discuss the selection of light sources and detectors.

Chapter 5: Data Transmission Interference

Topics: Electrical and process noise; Signal-to-noise ratio; Power line noise; Electromagnetic interference; Capacitive coupling; Ground loops; Noise reduction techniques; Electrostatic shielding

Learning Objectives:

• Define electrical noise, process noise, and the signal-to-noise ratio.
• Explain how ac power lines, EMI, capacitive coupling, and ground loops cause electrical noise.
• Describe two kinds of noise filters and explain three methods of reducing ac power line noise.
• Compare methods for reducing electromagnetic and electrostatic coupling.
• Discuss the use of differential measurements and the CMRR.
• Describe ways of reducing ground loop noise and RFI and explain when optical coupling might be used.

Request Exam Copies