THE PRESENCE OF IOT IN TODAY'S
WORLD:
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The Internet of Things (IoT) is all around us and quickly
expanding.
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We are just beginning to reap the benefits of the IoT.
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New ways to use connected things are always being
developed.
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The IoT helps individuals connect things to improve
quality of life.
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Consider how many people are now using wearable
devices to track their fitness activities.
example of a wearable shirt designed to track your
fitness level.
The IoT also helps organizations and industries improve
resource management to become more efficient.
Consider how the IoT is used in smart cities.
overview of how smart cites connect things to improve
the lives of its citizens.
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The IoT is helping industries including manufacturing,
utilities, oil and gas, transportation, mining, and public
and private sector organizations increase operationally
efficiency.
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Companies and cities are now increasingly deploying IoT
solutions.
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However, this rapid increase in growth has also
introduced new challenges including:
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How to integrate the millions of devices from
different vendors that use custom applications
How to integrate new things into the existing
network infrastructure
How to secure these new devices, each
configured with varying levels of security
To help address these challenges and help
organizations and industries adopt IoT solutions, Cisco
introduced the Cisco IoT System.
Specifically, the Cisco IoT System reduces the
complexities of digitization for industry.
As shown in the figure, the Cisco IoT System identifies
six technology pillars that help simplify and secure an
IoT
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Network Connectivity
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Fog Computing
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Cybersecurity and Physical Security
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Data Analytics
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Management and Automation
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Application Enablement Platform
To help address these challenges and help
organizations and industries adopt IoT solutions, Cisco
introduced the Cisco IoT System.
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Click here to see how Cisco is developing digitization
solutions for all types of industries.
Cisco Jasper Technologies is a company that provides
an IoT cloud platform enabling you to manage
connectivity for all your IoT devices.
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With Jasper, companies can use cellular networks to
connect to any device, from pacemakers to jet engines.
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Companies can then manage connectivity of IoT
services through the IoT cloud platform as a Service
(SaaS) platform.
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For more information on Cisco Jasper Technologies,
their IoT cloud platform, and customer IoT success
stories click here.
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There are many different types of IoT-enabled devices
available.
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However, most IoT devices use sensors, controllers, and
actuators to perform functions
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Feedback loops are used by the IoT device to provide
real-time information to its controller based on current
behavior.
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A closed loop exists when the feedback is continuously
being received by the controller from its sensors.
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The controller analyzes and processes information, and if
necessary, it can use actuators to modify conditions.
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This process is continuously repeated and adjusted.
SENSORS
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A sensor is a device that can be used to measure a
physical property by detecting some type of
information from the physical world.
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This information could be light, moisture, motion,
pressure, temperature, or any other environmental
condition.
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For example, in Figure 1, the coffee farm displayed
could use sensors to collect a variety of information,
such as sunlight, temperature, and soil moisture.
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This data can then be analyzed to help maximize
the yield and quality of coffee.
• A sensor may be connected to a controller either
directly or remotely.
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Sensors and controllers are usually connected by
means of analog or digital circuits.
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Sensors send data to a controller.
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That controller could react to the sensor data
immediately and change the actuator settings.
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As an example, a Controller Area Network (CAN)
is a standard used in most modern automobiles to
allow for communication between sensors and
controllers without any host computers.
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Most new cars are equipped with backup cameras
or anti-collision sensors.
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These cameras and their sensors can alert the
microcontrollers if an object is in the way and the
microcontrollers will automatically cause the car to
emit a warning signal or to apply the brakes.
A sensor may be connected to a controller either
directly or remotely.
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Sensors and controllers are usually connected by
means of analog or digital circuits.
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Sensors send data to a controller.
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That controller could react to the sensor data
immediately and change the actuator settings.
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As an example, a Controller Area Network (CAN)
is a standard used in most modern automobiles to
allow for communication between sensors and
controllers without any host computers.
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Most new cars are equipped with backup cameras
or anti-collision sensors.
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These cameras and their sensors can alert the
microcontrollers if an object is in the way and the
microcontrollers will automatically cause the car to
emit a warning signal or to apply the brakes.
ACTUATORS
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An actuator is a basic motor that can be used to
move or control a mechanism or system, based
on a specific set of instructions.
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Typically, in the Industrial IoT, there are three
types of actuators:
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Electrical - Powered by a motor that converts
electrical energy into mechanical operations
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Hydraulic - Uses fluid pressure to perform
mechanical movement
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Pneumatic - Uses compressed air to enable
mechanical operations
The example in the figure displays an industrial
actuator consisting of an electric solenoid used
to control hydraulics.
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for transforming an electrical signal into
physical output.
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This physical output could provide information
to a user via LEDs or modify another device or
environment.
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For example, the heater in the thermostat
feedback loop is an actuator because it
changes the status of the controlled
environment (temperature) in response to an
electrical signal.
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Regardless of how the actuator causes the
movement to be performed, the basic function
of an actuator is to receive a signal from the
controller, and based on that signal, perform a
set action.
CONTROLLERS
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Controllers are responsible for collecting data from
sensors and providing network or Internet
connectivity.
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Controllers may have the ability to make immediate
decisions, or they may send data to a more
powerful computer for analysis.
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This more powerful computer might be in the same
LAN as the controller or might only be accessible
through an Internet connection.
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Figure 1 displays a sample IoT topology consisting
of sensors, controllers, routers and data centers.
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To reach the more powerful computers in the data
center, the controller will first send data to a local
router.
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This router is the interface between the local
network and Internet.
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It can send data back and forth between them.
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Figure 2 displays a sample IoT topology that
highlights how controllers are used in fog
computing.
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Imagine smart traffic lights that contain sensors
and actuators.
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The sensors detect and report traffic activity to the
controller.
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The controller is able to process this data locally
and determine optimal traffic patterns.
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Using this information the controller will send
signals to the actuators in the traffic lights to adjust
traffic flows.
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This is an example of machine-to-machine (M2M)
communication.
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In this scenario, the sensors, actuators, and the
controller all exist within the fog.
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That means that the information is not sent beyond
the local network of end devices.
Figure 3 displays an example of IP-enabled
controllers.
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The IP-enabled controller forwards information
across an IP network, and allows individuals to
access the controller remotely.
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In addition to forwarding basic information in an
M2M configuration, some controllers are able to
perform more complex operations.
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Some controllers can consolidate information from
multiple sensors or perform basic analysis of data
received
The Arduino microcontroller, shown in Figure 4, and
the Raspberry Pi (RaPi), shown in Figure 5, are both
types of controllers.
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They can both operate without the Internet and are
used by hobbyists and professionals.
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The key difference between the two is physical size,
available processing power, memory, and OS.
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Typically the Arduino requires less power than the
RaPi and is more suitable for analog input.
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The application should dictate which controller is the
best to use.
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The two controllers are commonly used together.
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For instance, you can acquire data with the Arduino
and then process the data using the Raspberry Pi.
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More details about the Arduino and Raspberry Pi
controllers will be covered in a later chapter
IOT PROCESS FLOW
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Key components of some of the simplest IoT
systems include sensors connecting, through a
wireless or wired connection, to actuators or
controllers.
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Some devices can have more than one function.
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This is the case for the controller in an IoT System.
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A controller can collect data from sensors without
human intervention or network connectivity.
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As an example, a sensor determines that the
temperature in an apartment has dropped below a
pre-set level.
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The controller will process the data and send output
to cause the heater (the actuator) to turn on.
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A controller may also act as a gateway to the local
network.
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In the previous example, if the IoT system is
designed to capture the temperature changes
within every apartment of the building, the controller
may pass the data up to be stored or analyzed on
servers in the local or edge network.
PROCESSES
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As illustrated in Figure 1, a process uses inputs to
execute the right actions to achieve the desired
output.
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More formally, a process is a series of steps or
actions taken to achieve a desired result by the
consumer of the process.
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A system is a set of rules that govern the series of
steps or actions in the process.
FEEDBACK
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Feedback is when the output of a system, or
process, affects the input.
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To illustrate this, consider how feedback was used
to safely land on the moon (Figure 1). The computer
continually received altitude and speed feedback
measurements and displayed this information to the
astronaut and on-board systems.
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The astronaut used the feedback to control the
spacecraft and adjust altitude, engine, and thrust
levels to successfully land on the moon.
• Feedback is often referred to as a feedback loop.
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This is because the input results in output that is
continually resampled and used as new input, as
illustrated in Figure 2.
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The feedback loop represents the idea of a causeand-effect cycle, or circuit, where results
continually adjust actions.
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Many system processes normally have some type
of feedback loop mechanism.
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Systems usually have a way of looping or feeding
back information about the quality of the output.
Feedback loops can be positive or negative:
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Positive feedback - Feedback reinforces the
original input.
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Positive feedback accelerates the transformation
of the output in the same direction as the previous
result.
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It tends toward either exponential growth or
decline, as shown in Figure 3.
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Negative feedback - Feedback cancels out or
counteracts the original input.
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Negative feedback diminishes the effect of the
previous result.
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It tends towards stabilization, reaching some level
of equilibrium, as shown in Figure 4.
CONTROL SYSTEMS
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A control system includes a controller that uses
inputs and outputs to manage and regulate the
behavior of the system in an attempt to achieve a
desired state.
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The input specifies what the output should be for
the whole process.
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The controller indicates what specific changes are
needed to achieve the desired output based on the
input.
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The controlled portion of the system, the process
and the actuator, is often called the plant.
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The input is used by the plant to produce the
desired output.
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Choosing the adjustments to apply to a plant to
achieve a desired output is called control theory.
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Control theory is essentially a strategy to select the
correct input and how to go about generating the
desired output.
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Control theory is applied in all types of devices.
• Consider how control theory is applied when
driving a car.
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The driver of the car is the controller, managing
and regulating the car (the plant).
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Based on the input, the driver determines how to
use each control (e.g., accelerator, brake, steering
wheel) to achieve the intended output.
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Many of the processes in a car also depend on
control systems designed by the automobile
manufacturer.
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In these control systems, the output is measured
using some type of sensor to inform what changes
a controller needs to make.
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The goal is to design a system with an error rate
of zero.
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This means that the output of the plant is exactly
what you want it to be.
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Therefore, if a driver wants to travel at 65 MPH,
then setting the cruise control to 65 MPH should
achieve exactly that result.
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On a greater scale of technology, consider how
control theory was applied to successfully land the
NASA Curiosity Rover on Mars.
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The rover used a dynamic control system to
determine how to move through space.
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The rover sensors provided input by repeatedly
sampling its position and velocity during its descent
to the surface of Mars.
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Processes in the rover used this input to make the
necessary adjustments to land at the intended
destination.
• Control systems can be open-loop or closed-loop
systems.
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The difference between these two systems is
based on whether it uses feedback or not.
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Click here to view an excellent 9-minute video that
explains open-loop and closed-loop control
systems.
OPEN-LOOP
CONTROL SYSTEMS
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Open-loop control systems do not use feedback.
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The controller instructs the plant to perform a
predetermined action without any verification of
the desired results.
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A logic diagram of an open-loop control system is
displayed in the figure.
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Open-loop control systems are often used for
simple processes where the relationships between
the input and the plant are well-defined.
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The job of the engineer is to determine how to
manipulate the inputs so that the plant will
generate the desired outputs.
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For example, consider a coffee maker (the plant) as an
open-loop control system.
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The user provides the right amount of coffee and water
(the inputs).
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The plant heats the water and controls the flow of hot
water into the filter basket.
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The output is coffee.
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Assuming the plant is in proper working order, the quality
of the coffee (the output) is determined by the quality of
the inputs.
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Another example of an open-loop control system is a
home appliance.
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A dishwasher (the plant) typically runs for a set amount of
time using soap and hot water (the inputs).
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The plant, with its optimally-placed spraying jets and dish
racks, produces clean dishes (the output).
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However, the plant has no ability to determine when or if
the dishes are clean.
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The plant will run its full cycle regardless of the quality of
the input.
Did the user load exceptionally dirty dishes? Did the user
add soap?
Note that in both examples, the quality of the inputs directly
impacts the quality of the output.
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CLOSED-LOOP
CONTROL SYSTEMS
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A closed-loop control system uses feedback to
determine whether the collected output is the
desired output.
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As shown in the diagram in Figure 1, a closed-loop
system measures output using a sensor.
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Using control theory, this measurement is
compared to a reference that represents the
desired state (input).
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The result is then “fed back” into a controller.
This feedback is used by the controller to adjust the
controls into the plant for the next iteration of output,
and the process repeats.
• There are many examples of closed-loop control
systems.
For example, consider the
diagram of a home heating,
ventilation, and air conditioning
(HVAC) control system in Figure
2.
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Initially, the digital thermostat is
programmed with the desired temperature.
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This input is fed into the HVAC plant. If necessary,
the plant engages the HVAC equipment, to
generate the desired output.
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The resulting output is measured against the
desired input.
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The error, or difference, between the desired and
measured temperatures is determined and the
thermostat adjusts the control to the HVAC plant.
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There are many types of closed-loop controllers.
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A proportional-integral-derivative (PID) controller is
an efficient way to implement feedback control.
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PID controllers are used in many types of industrial
applications because they are simple to use.
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PID controllers are easy to understand, implement,
test, and troubleshoot.
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The Arduino® and Raspberry Pi® devices can be
used to implement PID controllers.
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As mentioned earlier, the acronym PID stands for
proportional, integral, and derivative.
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Each of these terms describes how an error is
handled.
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Although the math is beyond the scope of this
course, the meaning of these terms can be
explained using the graphs in Figure 2.
• Proportional controllers (P) – These controllers
look specifically at the difference between the
measured output and the desired output.
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The amount of change sent to the plant by the
controller is proportional to the size of the error
from the last iteration.
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For example, in an HVAC system the controller
would activate 50% of the chillers if the sensor
detected a one degree deviation from the set
temperature.
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At 2 degrees deviation, 100% capacity would be
activated.
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Proportional controls will usually overshoot the set
temperature, as shown in the P graph because
they are only looking at the deviation from the set
point at any given time.
ntegral controllers (PI) – These proportional and
integral controllers use historical data to measure
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how long the system has deviated from the set
temperature.
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The longer the system has deviated from the set
temperature, the larger the response from the
controller.
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In an HVAC system, the controller would account
for historical data and time when adjusting the
system.
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Although integral controllers will also overshoot
the set temperature, the variation will decrease
overtime, as shown in the PI graph.
Adding Derivative controllers🡪 (PID) – These
proportional, integral, and derivative controllers
include data about how quickly the system is
approaching the desired output.
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In an HVAC system, the derivative function of a
PID controller looks at the rate of change in
temperature.
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This allows the controller to quickly adjust the
output as the system approaches the desired
output, as shown in the PID graph.
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INTERDEPENDENT
SYSTEMS
Closed-loop control systems are simple to
understand.
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However, there can be considerable complexity in
the real world.
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Many factors can impact systems, and the extent
of their impact is not always easily measured.
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Most systems have many interdependent pieces
contributing to and affecting the output.
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For example, consider a healthy lifestyle system,
as shown in the diagram.
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A person embarks on a program of diet and
exercise.
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After a short time, they become stronger and their
clothes fit more loosely.
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They begin to receive compliments (feedback)
from others.
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This results in good feelings that motivate them to
continue their diet and exercise.
Another example is the Earth’s climate system.
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The diagram in Figure 2 shows how rising global
temperatures cause arctic ice to melt faster,
thereby increasing the amount of ocean surface.
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Increased ocean surface means less sunlight is
reflected back into space, which increases the
temperature of the earth.
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Finally, consider the example of
materials back into the supply chain.
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Click here to learn about how Dell is recycling the
plastic from old electronics back into the supply
recycling
chain, which is used to manufacture new computer
systems.