CramPuppy - Free Revision Notes » Gcse » Information-technology » Sensors, Control And Data Logging
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Date: Wed, 2 Aug 2006 Time: 12:00 AM
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Sensors, Control And Data Logging
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A sensor measures a physical variable such as heat or moisture.
The value of the variable is then input into a CPU ( Central Processing Unit )
Sensors monitor a physical variable and record its values. These data values are then converted into information.
The logging period
This is the duration that the physical variable will be measured for.
For the monitoring of temperature the period might be 24 hours.
For the cooling of boiling water it might only be 10 or 15 minutes.
The logging interval
This is the amount of time that will exist between readings.
For example, if temperature was being monitored, then the interval might be every 15 minutes.
If it was the cooling of boiling water, the interval would probably be every 10 seconds.
The interval should always be sensible and appropriate to the variable being measured.
Everyday examples of logging
- Traffic surveys - pressure sensor monitors the number of vehicles
- Speed cameras - speeding and going through on red sensors
- Telephone bills - time, date, length of call, who call is to
CONTROL SYSTEMS
Controlling the temperature of a refrigerator
Feedback
Feedback is used to control the status of the motor ( on or off ).
Definition:- Input affects output which in turn affects input.
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by: Admin
Total views: 832
Word Count: 442
Date: Wed, 2 Aug 2006 Time: 12:00 AM
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