What is Data Acquisition?

Data acquisition systems, as the name implies, are products and/or processes used to collect information to document or analyze some phenomenon. In the simplest form, a technician logging the temperature of an oven on a piece of paper is performing data acquisition. As technology has progressed, this
type of process has been simplified and made more accurate, versatile, and reliable through electronic equipment. Equipment ranges from simple recorders to sophisticated computer systems. Data acquisition products serve as a focal point in a system, tying together a wide variety of products, such as sensors 
that indicate temperature, flow, level, or pressure.

Data acquisition systems typically convert analog Physical condition into digital values for easy processing.

Parts of a DAQ System
  • Sensor
  • DAQ Device
  • Computer
What Is a Sensor?
The measurement of a physical phenomenon, such as the temperature of a room, the intensity of a light source, or the force applied to an object, begins with a sensor. A sensor, also called a transducer, converts a physical phenomenon into a measurable electrical signal. Depending on the type of sensor, its electrical output can be a voltage, current, resistance, or another electrical attribute that varies over time. Some sensors may require additional components and circuitry to properly produce a signal that can accurately and safely be read by a DAQ device.

What Is a DAQ Device?
DAQ hardware acts as the interface between a computer and signals from the outside world. It primarily functions as a device that digitizes incoming analog signals so that a computer can interpret them. The three key components of a DAQ device used for measuring a signal are the signal conditioning circuitry, analog-to-digital converter (ADC), and computer bus. Many DAQ devices include other functions for automating measurement systems and processes. For example, digital-to-analog converters (DACs) output analog signals, digital I/O lines input and output digital signals, and counter/timers count and generate digital pulses.

Key Measurement Components of a DAQ Device
  1. Signal Conditioning
  2. Analog-to-Digital Converter (ADC)
  3. Computer Bus
What Is a Computer’s Role in a DAQ System?
A computer with programmable software controls the operation of the DAQ device and is used for processing, visualizing, and storing measurement data. Different types of computers are used in different types of applications. A desktop may be used in a lab for its processing power, a laptop may be used in the field for its portability, or an industrial computer may be used in a manufacturing plant for its ruggedness.

What Are the Different Software Components in a DAQ System?
Driver Software
Driver software provides application software the ability to interact with a DAQ device. It simplifies communication with the DAQ device by abstracting low-level hardware commands and register-level programming.
Application Software
Application software facilitates the interaction between the computer and user for acquiring, analyzing, and presenting measurement data.

Comments

  1. Harsha22 July 2016 at 11:33

    Can you explain what is Signal `Conditioning`

    ReplyDelete
    Replies
    1. nmarshal23 July 2016 at 22:15

      Signals from sensors or the outside world can be noisy or too dangerous to measure directly. Signal conditioning circuitry manipulates a signal into a form that is suitable for input into an ADC. This circuitry can include amplification, attenuation, filtering, and isolation. Some DAQ devices include built-in signal conditioning designed for measuring specific types of sensors.

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