Hi friends,
 
In this article, I am going to discuss the data acquisition system block diagram, function of each block, and its applications. This article will provide you an overview about data acquisition system in simple words.
 
Data acquisition system (DAS) is a computerized system that collects data from the real world, converts it into the form of electrical signals and do required processing on it for storage, and presentation on computers.
 
The complete system is controlled and operated by a software application. This software application is developed by using general-purpose high-level programming languages like C, C++, java, etc.
 
These systems are used in industrial and commercial fields. They are used for collecting, storing and processing of data.
 
The data acquisition system can be divided into two types:

  • Analog data acquisition system
  • Digital data acquisition system

The analog data acquisition system gives an analog output whereas the digital data acquisition system gives a digital output.
 
Analog DAS is used when wide frequency width is required or when lower accuracies can be tolerated.
 
Digital DAS is used when physical quantity being monitored has a narrow bandwidth (i.e. when the quantity varies slowly). Also, high accuracy and low per channel cost are required. These are more complex than analog DAS.
 
The digital data have more advantages over analog data. Some of those are:

  • easy and fast processing,
  • easy and fast transmission,
  • easy display,
  • less storage space is required,
  • more accurate.

Due to these advantages, mostly the digital data acquisition system is preferred.
 

Data Acquisition System Block Diagram

 
A generalized data acquisition system block diagram is shown in Figure.

data acquisition system block diagram pdf

The function of each block is as under:
 
Transducers: They are converting physical quantities (such as temperature, pressure, etc.) into electrical quantities, or measuring electrical quantities directly. They collect data from the physical world.
 
The most commonly used transducers are:

Signal Conditioning Unit: The signal produced by the transducers may or may not be very suitable for our system to work properly. It may be very weak, very strong or may have some noise.
 
To convert this signal into the most suitable form, amplification, and filtration is done respectively by signal conditioning unit. So the signal conditioning unit converts electrical signals in the most suitable form.
 
Multiplexer: The multiplexer receives multiple analog inputs and provides a single output signal according to the requirements.
 
If a separate channel is used for each quantity, the cost of installation, maintenance, and periodic replacement becomes high. Therefore, a single channel is used which is shared by various quantities.
 
Analog to Digital (A/D) Converters: The data is converted into digital form by A/D converters.
 
After the conversion of data into digital form, it is displayed with the help of oscilloscopes, numerical displays, panel meters to monitor the complete system.
 
Also, the data can be either permanently or temporarily stored or recorded according to the requirement. The data is recorded on optical, ultraviolet, stylus or ink recorders for future use. 
 

Objectives of Data Acquisition System

 

  • It must collect the necessary data at the correct speed.
  • It must use all the data efficiently to inform the operator about the state of the system.
  • It must monitor the complete system operation to maintain on-line optimum and safe operations.
  • It must be able to summarize and store data for the diagnosis of operation and record purpose.
  • It must be flexible for future requirements.
  • It must be reliable and not have a downtime of more than 0.1%.
  • It must provide an effective communication system.

Applications of Data Acquisition System

 
The data acquisition system is used in industrial and scientific fields like aerospace, biomedical and telemetry industries.
 
Thanks for reading about data acquisition system block diagram.
 

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1 Comment

Erika Brady · 09/26/2019 at

Thanks for explaining the difference between analog and digital data acquisition systems and how they give different types of output. When choosing one, it would probably be important to figure out the output you need to be able to work with it. Once you’ve figured out the type of system you need, it would probably be a good idea to go online to find companies that sell data acquisition systems and parts in order to find one that can provide the type you’re looking for.

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