Data Acquisition System:
A data acquisition system is a type of information system that gathers, stores, and delivers data. It gets used to collect electrical signals or environmental conditions on a computer device in industrial and commercial electronics, as well as environmental and scientific equipment. A data logger is another term for a data-gathering system.
DAQ is a wide word that encompasses a variety of instruments and technologies used to collect data. DAQ systems typically include DAQ software and hardware, as well as actuators and sensors and they require underlying network infrastructure for data transfer between the data collection hardware and software. It further gets characterized into the single and multi-channel data acquisition system.
The hardware is often made up of external expansion slots. These can get linked to the computer via a communication medium such as PCI or USB, or they can get mounted directly into the motherboard.
Types of Data Acquisition Systems:
Single-channel Data Acquisition system:
A signal processor and an analog-to-digital converter that conducts recurring conversions at a defined free operating rate comprise a Single Channel Data Acquisition System.
The outputs are in digitized code words and contain an indication of overshoot, polarity statistics, and a status report that shows if the output numbers are valid.
Analog-to-digital converter
Data acquisition System analogue to digital converters is frequently designed to receive external conversion and hold orders. A dual slope type converter gets used for alternating current and low-frequency transmissions. It has the advantage of being linear averaging capability and having a blank reaction for frequencies related to the averaging period.
Dual slope A/D converters aid in the conversion of low-frequency data, such as thermocouple data, especially in the presence of noise. Because it can give high resolution and quick speed at a reasonable cost, the successive approximation kind of converter is the most popular for data system applications.
Utilizing a sample hold preceding the A/D converter allows for faster rates. The samples hold becomes especially critical with A/D converters of the sequential estimation type, as the latter creates considerable non-linearity problems at higher rates of input change. After all, it cannot accept alterations during the conversion process.
When data get sent through a noisy environment, direct digital conversion conducted near the signal source is particularly beneficial.
Multi-channel data acquisition system
In the Multi-Channel Data Acquisition System, two or more input sources can share time. Depending on the needed properties of the multiplexed system, several approaches get used for equivalent time-shared measurements.
Analog Multiplexed System
In the multi-channel data acquisition system, a single A/D converter comes before the multiplexer. Individual analogue signals get sent to the multiplexer either directly or after enhancing and/or signal to process, as necessary.
When the acquisition is complete, either instantly or on demand, the S/H switches to retention mode, a transformation begins, as well as the multiplexer selects the next channel. This technique is slower than devices that multiplex S/H outputs or maybe A/D converter outputs, however, it has the evident benefit of being less expensive due to the sharing of the majority of sub-systems.