ALL YOU NEED TO KNOW ABOUT DATA ACQUISITION Data Acquisition: Data Acquisition is the process which involves gathering signals that measure the real world physical condition and digitizing those signals to be displayed on a PC. The Data Acquisition System is abbreviated as DAQ or DAS.
Historical Facts: - IBM produced computers in 1963. These computers specialized in Data Acquisition System. - In 1974, these systems were replaced by general purpose S-100 computers and DAQ cards produced by Tecmar/Scientific Solutions Inc. - In 1981, IBM introduced IBM personal computer and scientific solutions. These introduced the first PC Data Acquisition products.
In an ideal DAQ there are five components: -
Transducers Signals Signal Conditioning
Data Acquisition hardware Drive and Software
Let’s discuss in detail.
What are Transducers? Transducers act as sensors. The function of Data Acquisition is to determine the physical phenomenon to be measured. This physical phenomenon could be a varied number of things like temperature, the pressure in a room and so on. Data Acquisition will help you in measuring that physical phenomenon to an electrical signal. The device used for that conversion is called as Transducer.Every Transducer functions in a different way. Some examples of Transducers are given below: -
Thermocouple (Temperature Measurement) Microphone (Sound) Photosensor (Light), and so on.
What are Signals?
Signals are formed when Transducers convert a physical phenomenon to a format that can be presented on a PC. There are different types of signals as given below. -
Analog Digital
Analog Signals: These signals can exist at any value with respect to given time. There are three characteristics of Analog Signals. -
Level: Level gives us information about the analog signal that is being measured. Shape: The shape of the signal gives us insight that is helpful in further analyses of the analog signal. The shape could be sine, square or triangle. Frequency: It is the most important piece of information. You cannot directly measure frequency for a signal. Therefore, a specific algorithm is used to measure the frequency of a signal.
Some types of Analog Signals are voltage, sound, pressure and so on. Digital Signals: These signals cannot take any value with time. Digital Signals can be measured in two levels: high and low. These signals are commonly referred to as TTL (transistor-to-transistor logic). You can measure the “State” and the “Rate” of the physical phenomenon with the help of digital signals.
Why do we need Signal Conditioning? Conditioning of a signal is a very important part of DAQ system. In case we are dealing with Physical conditions like high voltage or an extremely noisy environment. In this case Signal Conditioning proves to be helpful. How? It will convert the signal to a safe and clear format. Some examples of this process are Amplifying, attenuation and so on. it is very important for an ideal Data Acquisition Module to have signal conditioning.
All about Data Acquisition Hardware: Data Acquisition Hardware acts as the connecting interface between a PC and the physical world. As the signals have to be interpreted by the PC, they first have to be converted to a digital format. DAS hardware helps us with that. It is in the form of a module to be connected to PC ports or cards connected to slots. The following are the components: -
Analog input/ output (Analog IO module) Digital input/output (Digital IO module) Counter/Timers Multifunction (Combination of all)
Drives and Software: -
For a Data Acquisition hardware to work with the PC, it requires a device drive. A DAQ software might also be delivered with DAQ hardware. It consists of all the tools to build a Data Acquisition System.
There are various platforms available to get DAQ or DAS hardware. Contact a professional for more information.
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