Monitoring and Control Flashcards
(19 cards)
Sensor
Collects data about physical environment automatically
12 types of sensors :(
- light/UV (car park barrier system)
– temperature
– pressure
– humidity (measure water content of soil)
– pH (measure the acidity of soil)
– gas sensors
– sound (burglar alarm systems)
– infrared (detect movement in burglar alarm)
– touch sensors
– electromagnetic field sensors
– proximity sensor ( in smartphones to switch off screen when phone is near ear)
Sensor advantage
-data is continually monitored
-if an event happens it will not be missed
-can monitor 24/7
-no human error in typing in data
-can be monitored remotely
-no risk to humans in dangerous areas
-more accurate than human
Sensor disadvantage
-interruptions to power supply could cause sensor to stop working
-failure of equipment could cause data to be inaccurate/missed
-has to be maintained by humans
Calibration
Need reference such as other sensor or physical reference (ruler)
Offset (like zero error)
Sensitivity (how much change in physical will it respond to)
Linearity (consistency of measurements over the entire range of measurements)
improves accuracy of sensors after they have become inaccurate
one point calibration
only one measurement point is needed
two point calibration
Fix offset and sensitivity
take 2 different readings on lower end and high end
compare to ideal
and use formula to correct each value
multi point calibration
performed using multiple readings
more accurate and helps with linearity
Monitoring system
Collect data and store it to analyze in future
Uses storage devices, sensors , graphing software
Examples of monitoring system
– environmental monitoring
○ monitoring water pollution
○ weather stations, use of sensors
○ temperature sensors to measure ambient temperature
○ pressure sensors to measure atmospheric pressure
○ humidity sensors to measure absolute and relative humidity
○ light sensors to measure sunlight
– environmental patients
Control system
Collect data and send to computer to analyze and take action
Uses sensor, microprocessor, actuator
Microprocessor
Electronic component that can perform similar functions to CPU
can also hold small amount of data in register
Adv/dis of microprocessor
Can be programmed to execute several different tasks
Small in size
can overheat
limit on size of data can hold
Actuator
Used to move/operate mechanisms or devices
Actuator types
○ linear
○ rotary
○ soft
○ hydraulic
○ pneumatic
○ electric
○ thermal
○ magnetic
○ mechanic
Examples of microprocessor controlled technology
– greenhouses
– central heating systems
– air conditioning systems
– burglar alarms
– control of traffic/pedestrian flow (including smart motorways)
– car park barriers
– traffic lights
– Wireless Sensor and Actuator Networks
– smart homes
how data logging is done
sensor used to gather data
name a sensor
data collected is analogue
analogue to digital convert converts data to digital
so can be understood by computer
computer analyses data
presents results in graphs
adv disadvantage of using computer system to monitor
-data can be displayed/analyzed in real time
-data is immediately sent to computer
-computer systems can monitor multiple sensors simultaneously
-Maintenance can be expensive
-data logger cannot react to emergencies
how microprocessor used to control items
-sensor identifies if ___
-name sensor ____
-If _____ microprocessor sends signal to acutator
-process is constantly repeated (depends on situation)
-If ___ then _____
-Data is sent to ADC
-ADC converts data to digital so microprocessor can understand
