Design for
Unit 4: Instrumentation
and Control Systems
Definition of terms relating to instrumentation and
control systems
Describes a method of storing,
processing and transmitting
information through the use of
distinct electronic or optical
pulses that represent the binary
digits 0 and 1. Digital
technologies employ a sequence
of discrete, distinct pulses to
represent information, as
opposed to the continuously
variable analog signal. DS-0,
Information in a
continuously variable form.
A useful illustration is to
think of analogue
information as being
represented by an infinite
number of shades of grey,
rather than being
represented by just pure
black or pure white. Sound
recorded on a vinyl record,
for example, is analogue in
nature. Traditional telephone
and television technology is
also analogue technology.
A numbering system using the
digits "0" and "1" in the decimal
system. An example of this is all
computer programs are executed
in binary form.
A circuit of transistors and
other electrical components
on a chip that can process
programs, remember
information, or perform
An example is the central
processing unit on
Fuzzy Logic
A conclusion reached by a computer
recognizing that all values are not absolutes
such as yes or no, black or white etc. Fuzzy
logic makes calculations considering values in
varying degrees between absolutes. For
example, a computer might recognize black
and white as absolutes, yet make an
evaluation based on a shade of grey, which is
somewhere between.
Neural Systems
A neural system consists of a set of
highly interconnected entities,
called nodes or units. Each unit is
designed to mimic its biological
counterpart, the neuron. Each
accepts a weighted set of inputs
and responds with an output.
Examples include speech synthesis,
diagnostic problems, medicine,
business and finance, robotic
control, signal processing,
computer vision and many other
problems that fall under the
category of pattern recognition.
An electronic device used to
measure a physical quantity such
as temperature, pressure or
loudness and convert it into an
electronic signal of some kind. An
example is that in many solar
heating systems there are
sensors. These systems sensors
measure freeze temps, outside
temps, Water temps, Solar Panel
Temps, and several other factors.
Actuators are devices that make
changes to the environment in
response to signals. Actuators can
be classified according to the
power that makes them work electrical, pneumatic or hydraulic.
Examples are motors, in one form
or another, used in a remote
control toy.
Stepper motor
A device that translates electrical
pulses into precise mechanical
movement. An example is a motor
used to drive the gears which turn
the hands in a quartz analog watch.
Synchro motor
The synchro drive system is a
two motor, three/four wheeled
drive configuration where one
motor rotates all wheels to
produce motion and the other
motor turns all wheels to
change direction.
Open-loop control
A control system which does not take any account
of the error between the desired and actual values
of the controlled variables. A characteristic of the
open-loop controller is that it does not use
feedback to determine if its input has achieved the
desired goal. This means that the system does not
observe the output of the processes that it is
controlling. A typical example would be a
conventional washing machine, for which the
length of machine wash time is entirely dependent
on the judgement and estimation of the human
Closed-loop control
Systems that utilize feedback
are called closed-loop control
systems. The feedback is used
to make decisions about
changes to the control signal
that drives a device. An
example is if feedback indicates
that the temperature in your
home is below your desired set
point, the thermostat will turn
the heater on until the room is
at least that temperature.
Devices or instructions installed or
inserted into hardware or software to
monitor the operation of a system or
component. An example of this is
using a voltage meter to see how
much amperage is coming from an
electrical device.
Standard #2: Students will develop an understanding of the core concepts of technology
Y. The stability of a technological system is influenced by all of the components in the
system, especially those in the feedback loop.
DD. Quality control is a planned process to ensure that a product, service, or system meets
established criteria.
FF. Complex systems have many layers of controls and feedback loops to provide
Standard #3: Students will develop an understanding of the relationships among technologies and
the connections between technology and other fields of study.
H. Technological innovation often results when ideas, knowledge, or skills are shared within
a technology, among technologies, or across other fields.
J. Technological progress promotes the advancement of science and mathematics.
Standard #17: Students will develop an understanding of and be able to select and use
information and communication technologies.
M. Information and communication systems allow information to be transferred from human
to human, human to machine, machine to human, and machine to machine.
O. Communication systems are made up of source, encoder, transmitter, receiver, decoder,
storage, retrieval, and destination.
P. There are many ways to communicate information, such as graphic and electronic means.
Q. Technological knowledge and processes are communicated using symbols, measurement,
conventions, icons, graphic images, and languages that incorporate a variety of visual,
auditory, and tactile stimuli.

Design for Engineering