Chapter 8: Controls & Displays (TEST 2) Flashcards
What is a display and its purpose
A display is a device or interface that presents information to the user.
To convey information about a certain entity in our environment or surrounding
Types of display
visual, auditory, tactual, and olfactory
Main issue of visual displays
easily overloaded
Types of visual displays
- Quantitative
- Qualitative
- Check Reading
- Situation Awareness
Quantitative display
Numerical information is critical to decision-making
Changes in numerical information reflect system status
Usually digital or other fixed-number output
Qualitative display
Approximates values, trends, rate of change or direction
Shape, spatial arrangement, movement, and color convey meaning
There is a range of normality or abnormality
Check Reading display
gives you the status of parameter
Situation Awareness display
similar to check reading, but used to aid
in prediction of future states
Ex: gas is low indicator tells you that you will run out of gas soon
What is the main issue of Auditory displays
reduction in hearing ability over a workday for noise environments/fading into background noise
Purpose of Auditory displays
Warning/alarm signals
Aids for the blind
Main issue of olfactory display
low sense of smell
one use of olfactory display
Warnings( e.g. rotten eggs for natural gas leak)
Tactual display’s main issue
rarely used, difficulty in using body parts other than the hands
What is a control
A control is any interface element or device that a user can manipulate to operate or influence a system or machine
Purpose of a control
Transmit information to some device, mechanism, or system
Discrete
limited number of conditions
Continuous
infinite number of options
Name all 5 Types of coding for ease of identification
Color Coding
Shape Coding
Size Coding
Location Coding
Labeling
Color Coding
Using different colors to signify different functions
Shape Coding
Giving controls distinct shapes
Size Coding
Larger controls for more critical functions that need immediate attention
Location Coding
Grouping related controls together to help users find the right one quickly
Labeling
Adding clear and descriptive text to each control to clarify its function
Control-response ratio (C/R)
What is a Low C/R ratio and High C/R ratio
ratio of control movement to movement
of the system’s response
Low C/R ratios are sensitive
High C/R ratios are not sensitive
Why should controls have resistance
avoid inadvertent activation of the control
Dead Space
amount of control movement around the null position that doesn’t result in activation
Types of Resistance
Elastic
Viscous
Static/Coulomb
Inertia
Elastic Resistance
After movement of the control, it will return to the null position
Viscous Resistance
Amount of resistance related to velocity of control movement
What device does not have resistance
touchscreen
Static/Coulomb Resistance
Resistance is greatest at the initiation of control movement
Inertia Resistance
Resistance due to the mass of the mechanism (hard to start and hard to stop; hard to make fine adjustments)
Name all types of controls and their respective uses
Cranks & handwheels: Used to apply force
Knobs: Used to apply torque
Stick-type Controls
Multifunction hand controls: no need to look at the control to operate, operator is in
constant contact with the control
Foot Controls: Used for force
Multifunction
Name the 3 special control devices
Membrane Keypads
Speech Activated Controls
Eye Activated Controls
Membrane Keypads problems
Require more force—small activation area in the center of the key versus depression of keyboard key at any spot
Contact areas are difficult to locate (keys are not easily separable by touch, require visual contact to operate)
Speech Activated Controls problems
Limited vocabulary
Significant pauses between words
(requires training to speak like this)
Individual differences (accents may
interfere with word recognition)
Changes in voice due to fatigue, stress,
emergencies, etc.
Eye Activated Controls problems
Overburden visual system
Vibrations distort eye control
Distractions cause eye shifts
Delays in ensuring eye activation
