Industrial Automation

Industrial Automation is not a totally new concept. It has been practised in the industry for a long time. But the introduction of personal computers has revolutionised the automation industry providing easy access, custom software applications and so on.


Automation is a process where sensors/transducers are employed to 'sense' the signal, one or more controllers 'guiding' the operation involved and the desired output is achieved in the form of actuators/motors/physical parameters such as temperature/pH in a factory.


Sensors:
Pressure sensors

Position transducers

1. linear
2. rotary

A set of Linear Potentiometers/Position sensors

Proximity sensors

1. capacitive proximity sensors
2. inductive proximity sensors
3. photoelectric proximity sensors

Proximity Sensors

A Metal Proximity Sensor - an inductive type detector

Temperature sensors

1. Resistance Temperature Device (RTD)
2. Thermocouple (TC)
3. Thermistors

An industrial temperature sensor

Humidity sensors 
These sensors measure the relative humidity by converting the signals to desired voltage/current output.

Level sensors
Used to measure the level, for e.g. water level in a tank/ chemical level in a container.

Load cells
These are utilised to measure the weight in electronic form.


Inputs:
Analog input
4-20mA current input
0-10V voltage input

Digital inputs
push buttons

Controllers:
Process indicators
Timers
Counters
Temperature controllers - PID
PC-based controllers
Input-output modules
Programmable logic controllers (PLC): AC/DC inputs & outputs
Variable speed drives (VSD)/ Variable frequency drives (VFD)

A Gefran timer cum counter

A variable frequency drive/variable speed drive

Converters:
Converters are used to change the signal type from one to another. This conversion may take a form of analog signals to digital signals (ADC) or changing the signal medium such as RS232 serial type to RS485 two-wire type.

An RS232-RS456 Converter

Actuators:
Based on the controller output, actuators would perform the desired action to change the controlled variable. These are mostly motion-oriented, for e.g. motors, solenoid valves, electromagnetic relays etc.

- Solenoid valves (electrically controlled valves)
- Motors such as steppers, servos, permanent magnet types
- Voltage-controlled electromagnetic relays

A voltage-triggered electromagnetic relay: enclosure removed

Software:
Automation configuration software (between h/w and s/w)
Automation display software ( to display the controlled parameters)
Supervisory control & Data acquisition (SCADA)

SCADA software interface for process control