Data Acquisition – term was originated during early industrial period while electronic field was consolidating with latest products like ICs & processors.
Earlier all machineries were monitored by humans. With comming out of more & more sophisticated electronic components, technologies started developing to monitor & control machines.
The monitoring on machines required observing many parameters like Temperature, pressure, current, voltage, power, humidity etc. Based upon the data gathered, the electronic system, tried to control machines as per set rules.
The gathering of data related to various parameters – acquiring of data became a comman function for almost all controlling systems. This was known as Data Acquisition. Data Acquisition simply means a process whereby data is automatically acquired about real world parameters like Temperature , pressure, humidity, etc through various sensors.
This data can be immidiately processed for controlling or can be stored to be processed at later stage. Data Acquisiton can be done by individual modules called Data Loggers or can be done by computers attached with Data Acquisiton Card.
With the advent of more powerful processors – CPUs, later known as Micocontrollers, the data acquisition became more sophisticated providing more computing power to system itself. This reduced their dependency on PC – Computers.
Modern Data Acquisition System generally consists of a Microcontroller with memory , sensor conditioning circuit ,Power supply, sensors and sometimes display.
Microcontroller – This is the heart of the system. This microcontroller acquires all the data, processes it & then keep it in required form either in inbuilt memory or external memory. This ic have required processing power to anlyse the acquired data and then it provides the information as per requirement.
Sensors – sensors convert the phisical parameters like temperature, pressure, humidity etc into voltage or current so that it becomes easy for microcontrollers to process.
Sensor conditioning circuit. – Every sensor has its own characteristic. Though modern sensors are made with inbuilt electronics, many sensors are still 100%
mechanical ones. They have their own behaviour pattern. Many times sensor signals are overladden with noises generated by surrounding electrical equipments, power supply quality, distance of sensors from main system etc. This leads to false data and because of this sensor conditioning becomes necessary. So sensors are connected to this circuit first and the data from this circuit is forwarded to Microcontroller for further processing.
Power Supply unit – Apart from providing power to the system its main function is to provide clean power as the data gathered is in terms of voltages, it becomes mandatory for such systems to have very very clean power.
Display unit – This dispaly of information is dependent of user’s requirement. PC based data acquisition system uses pc monitor for the information while small individual systems may use Liquid Crystal Display (LCDs) or Seven Segment LEDs to show various parameters.
Small individual data acquisition system without any display is also called Data Logger. This data logger has limited computing power & mainly keeps record of the parameter to be monitored. This data then can be transfered to computer for further processing. While PC based data acquisition systems gather data, stores data and also provide processed data on a monitor.
For modern industrial environment Data Acquisition Syatem has become an integral & utmost necessary part of automation scenario.