ITpastabowl

9626 Information Technology study material.©

Monitoring and control

Monitoring system: A system that observes and often records the activities in a process

Control system: A system that manages or regulates a process by physically changing aspects of the system depending on collected data.

Sensors

A sensor is an input device that collects data from the surrounding physical environment.

Advantages of using sensors over humans

Data can be collected 24/7
Data can be collected in harmful environments
Sensor may be more consistent in the data that it samples.

Different types of sensors

Light/UV
Motion
Temperature
Pressure
Humidity
Sound
Infrared
Touch
Electromagnetic field
Proximity

Calibration

Calibration is the process of testing and modifying a device to make sure that it is taking the correct readings.
Simple method of calibration is to test readings against two sensors and compare both.

Three main categories of results that can be given by a sensor.

Offset- If the readings are higher or lower than the source
sensitivity- If the readings change over a range at a different rate
Linearity- If the readings are directly proportional to the reference

3 main types of calibration

One point (for offset)
Two point (for sensitivity and offset)

Multipoint (Offset, sensitivity and Linearity)

Monitoring systems

A monitoring system is designed to collect the data and then store it so that
it can be used at a later stage. Main technologies used in a monitoring system are sensors,
plotters, etc. Graphing software etc can also help create a visual representation of the data.

Control systems

A control system is designed to collect data and then send it to a computer so that it can be analysed.
Main technologies used in a monitoring system are sensors, microprocessors and sometimes actuators.
A Microprocessor is an integrated circuit that is used in monitoring and control systems.

Microprocessor
Advantages	Disadvantages
Can be programmed to execute many different tasks	Limit on the size of data they can handle
They are small in size so can be integrated into many different technologies	They are small in size and can overheat easily
They are relatively fast at moving data

An actuator is a type of motor that is used to move and operate another mechanism or device.

Actuator
Advantages	Disadvantages
Hydraulic and electric actuators are fairly quiet	Pneumatic actuators can be quite noisy
The cost of pneumatic actuators is relatively low	The cost of hydraulic and electric actuators is relatively high
Most actuators have moderate to high speed abilities to perform an action	Fluid leaks can be a problem in hydraulic actuators