Table 1: Consumer/Producer role distribution.
PRODUCER CONSUMER
Data acquisition manager
Alarm manager
Historical data manager
Plant state supervisor
2.3 Sensor Manager
This module is in charge of introducing, updating
and eliminating the sensors from the system; so this
module needs to have access to the Data Acquisition
Hardware (DAH). The DAH carries out the signals
from the sensors to the final computer. Then these
signals can be processed by the computer in order to
get the readings in real time.
2.4 Actuator Manager
The actuation control is done by this module; it will
take care of including, modifying and deleting the
actuators from the system, and it will also define in
which entry of the DAH it is connected. This
module offers an interface so that the user or the
rules can activate the different actuators that are
installed in the system.
The actuator manager offers digital and
analogical outputs in order to control different kinds
of switches, motors, etc. This is the part of the
system that will enable us with the capacity of
automation.
The actuator manager offers us the ability of
activating and deactivating the different components
of each plant over the distance. We can connect
ourselves to the plant via web or via mobile phone
and give orders to it. This will prove useful in
various situations like shutting down a plant if
desired, or a part of a plant (e.g. Water pumps), or
activating a plant that was idle.
2.5 Alarm Manager
This is one of the most important parts of the system
because it is here where we will be able to define the
behavior of the control that we want for our plants.
With the intention of creating a system capable of
giving a solution to a range of situations, as wide as
possible, we couldn’t define a specific control;
therefore, we decided to create an engine so the user
could define its own control.
We decided to use a rule-based-system (RBS)
where the user would define his own rule set.
Besides, we also had to make a special effort to
create a solution that could be used by users lacking
any knowledge of algorithms; this was achieved by
creating an interface that would guide the user
through, asking questions and offering different
possibilities, and translating them into an algorithm.
Each alarm can have as many conditions for
activation as desired. These conditions can be: a
sensor’s readings are over or under a certain value,
this value can either be a constant or another sensor,
or how long the condition has to be active to raise
the alarm. It is also possible to include a difference
between two different sensors, controlling these way
possible undesired fluctuations.
The alarm manager is composed of three
subsystems which deliver complementary but
different functionalities. The subsystems that
compose the alarm manager are the following ones:
- Alarm administrator. This subsystem takes
care of creating, modifying and deleting the
rules from the system. This will be the
subsystem that takes care of the alarm
database in which the characteristics,
conditions and actions will be stored.
- Alarm watchdog. The watchdog evaluates the
activation conditions of the rules in order to
detect the activation and deactivation of each
and every one of them; when it detects an
event it informs of it to the alarm dispatcher.
- Alarm dispatcher. This subsystem will give
instructions to other modules in order for the
actions to take place; such actions can
involve sending an SMS to a user to inform
of the alarm, activating an actuator so that it
can put the plant back in order, or both.
2.6 SMS Manager
This component introduces the functionality of
sending SMS to the users so they can know in every
moment if something is going wrong, and if it comes
to that, they can send an SMS to the plant to activate
or deactivate any actuators. This way we introduce a
lot of possibilities of remote controlling the plant.
The SMS sent by the user must be written
according to the specifications of the system so the
SMS manager can interpret the object of its action.
We have chosen to make the remote control over
mobile phone because it enables us to communicate
in places where an internet connection might not be
possible and because it is a cheap technology.
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