CONTROL SYSTEMS
V. Ryan © 2003 - 2009
|
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET BASED ON EXERCISE BELOW (CLOSED SYSTEMS) CLOSED SYSTEMS:
When designing a control system it is good practice to consider it as a
number of stages. For example; |
||||||||||||
|
|
||||||||||||
|
|
||||||||||||
|
||||||||||||
|
The temperature is constantly monitored and this is called feedback. As long as the sensor works, the computer processes and the printer prints out - feed back is taking place. |
||||||||||||
|
OPEN SYSTEMS |
||||||||||||
|
PDF FILE - CLICK HERE FOR PRINTABLE WORKSHEET BASED ON OPEN SYSTEMS A system that does not have feedback is an open
system. An open system normally works once and then stops. A good
example is seen below. A digital camera is used to take a photograph, it
is transferred to the computer where processing of the picture takes
place and finally a printout is produced. This is a closed system
because there is no feedback and no attempt is made to improve the
picture. |
||||||||||||
|
|
||||||||||||
|
When drawing a systems diagram the boxes are labelled and there is no need to draw pictures representing each stage. However, when attempting course work, adding drawings helps present the diagram in a more graphical way. The open systems diagram shown below represents use of a digital camera which is shown graphically above. |
||||||||||||
|
|
||||||||||||
|
QUESTION: Draw a systems diagrams to represent a closed system of your choice and an open system. |
||||||||||||
|
|
||||||||||||