Mechatronic Systems

Industrial Systems:
- Refers to the integration of control systems with industrial processes (such as power plants)
- Automating industrial processes:
o reduces human intervention in the decision making and manual command adjustments
o Can improve efficiency, consistency, and safety of the processes whilst reducing
overheads.
- Low-level controllers (PLCs) handle the actuator-sensor interactions, whereas the human
controller is only responsible for monitoring and situational setpoint changes.


PLCs:
- Widely used for the control and automation of processes in industrial systems.
- They are programmed and facilitate the communication and decision-making between sensors,
actuators, and command signals.
- Commonly used to govern one unit of a process. An array of PLCs can be used in parallel to
regulate multiple processes.


Industrial Automation:
- Automation is the field of controlling a process in a highly automated manner using either
electrical, mechanical, computational and/or chemical techniques.
- Making a system run by itself with little to no human intervention.


Purpose of Automation:
- Benefits:
o Safety – less human intervention means less human error.
o Automating “dull, dirty and dangerous” jobs – the repetitive or dangerous jobs can be
done by machines.
o Maximise runtime – automated plants can run 24/7.
o Efficiency – A control system can ensure that the process is run in the most efficient way.
o Process Optimization – Allows new methods to be used that don’t require humans. This
can improve efficiency.
o Automated processes are less costly to run owing to the points above.
o Job creation – Engineering jobs in automated industrial systems
o Automated quality checks
- Risks:
o Job loss – machines take over low-skilled jobs.

, o High initial cost – Expensive to set up.
o Some tasks cannot be automated yet.
o Could be more costly (even in the long run) than manual manufacture.


Industrial Process Control:
- An industrial process is a series of unit processes connected in a production facility.
- Manufacturing, testing, and packaging are major industrial processes that require automation.
- The objectives of industrial processes are maximizing output and efficiency while minimizing cost.
- The Objective of industrial process control is to maintain a sustainable, long term, stable
operation.
- Certain technical limitations and other considerations should be considered:
o Availability of technology
o Local support for technology
o Cost of tech.
o Support from management
o Support for operation and maintenance


Industrial Process Hierarchy (System of Control):
- A framework designed to meet a specific objective such as best profit or return on investment
after accounting for all provisions (safety, environ. protection, etc).
- The most basic control strategy is at the bottom and each layer above it builds up until business
management.
o Higher Layers
 Overarching objective of the whole system. Desired product, profitability, efficiency
(long-term)
 Human intervention stage within the industrial process control (slowest response –
weeks or months)
o Middle Layers
 Strategies - Operational decisions (ensuring components work together)
 Control system which reads data from sensors and actuators (PLCs).
o Lower Layers
 Focus on individual tasks (sensors and actuators – building blocks of process unit)
 Individual tasks achieve operational decisions made for overall objective.
Control System:
- Links all functional units in an industrial system

, - Uses Top-down approach. High level (planning, business) is linked to the lower-level control
loops. Produces higher profitability as high-level objectives are met.
- Consists of planning, execution and control which must communicate together:
o Planning involves management of resources, materials, product orders, and operations.
o Control forms the material management, quality assurance and compliance with
management protocols and standards. All systems are integrated here, and all costing is
done here. Ensures efficiency of material usage.
o Execution is the control methodologies and instruments used (sensors, actuators, safety
systems). Generally some form of human interface to influence this part of the control
system.


History of Industrial Processes:
- Always a need to improve efficiency, productivity, and plant availability.
- Centralised Control Systems (greatly improved productivity):
o Includes indicators and alarms for every sensor and actuator on the plant.
o Allows plant operators to quickly see what was wrong in the plant.
o Downfall was that the control system was difficult to use owing to the information on the
display panels being difficult to interpret.
o As time passed, the process control become more centralised, introducing advisory and
supervisory control.
 Advisory control used analogue instrumentation and computers were used to
monitor and data log. Operators has little to no control but had to be present to
operate the system manually.
 Supervisory control used computers to improve control and calculate setpoints
for analogue controllers.
o The benefit of a computer was:
 Process Data and present it in a more usable form
 Flexible (can be programmed and reprogrammed)
 Could perform more complex calculating and control operations
 Information processing allows for management information to be readily extracted
and recorded.
 Lowering capital cost.
o Direct digital control used computers in the control loop to read in process signals and
output correcting signals to control plant at setpoints that were indicated by an operator.
The computer would then return the process information to the operators as displays on
printouts.