Diana Valentine

Engineering marvel of Data Acquisition Systems

Data acquisition starts with the physical property of an object to be measured that is analyzed and stored in the computer for long term purposes.

In short data acquisition systems are also referred to as DAS or DAQ which generally includes acquisition of signals and waveforms and then interpretation of signals to obtain desired information. These different properties which are analyzed through data acquisition are facts such as temperature, pressure, density, viscosity etc.

Data acquisition systems have a huge use in scientific and medical research purposes such as magnetic resonance imaging, microelectrode recording, and Eco cardiology, remote monitoring, laser Doppler flow etc.

They serve as an important part of gathering any vital information using data analysis software and equipments.

Some of the common forms of data acquisition at larger scale are seismic data acquisition, wireless data acquisition, pc data acquisition and SCADA (supervisory Control and Data Acquisition) which is the most widely used system referring to a computer system monitoring industrial, infrastructure or facility based processes like manufacturing, production, power generation, water treatment distribution and energy consumption.

Let’s get familiar with some more technical terms in data acquisition:

·         Analog-to-digital converter (ADC) An electronic device that converts analog signals to an equivalent digital form. The analog-to-digital converter is the heart of most data acquisition systems.

·         Digital-to-Analog Converter (D/A)
An electronic component found in many data acquisition devices that produce an analog output signal.

·         Digital Input/Output (DIO)
Refers to a type of data acquisition signal. Digital I/O is discrete signals which are either one of two states. These states may be on/off, high/low, 1/0, etc. Digital I/O is also referred to as binary I/O.

·         Differential Input
Refers to the way a signal is wired to a data acquisition device. Differential inputs have a unique high and unique low connection for each channel. Data acquisition devices have either single-ended or differential inputs, many devices support both configurations.

·         General Purpose Interface Bus (GPIB)
Synonymous with HPIB (for Hewlett-Packard), the standard bus used for controlling electronic instruments with a computer. Also called IEEE 488 in reference to defining ANSI/IEEE standards.

·         Resolution
The smallest signal increment that can be detected by a data acquisition system. Resolution can be expressed in bits, in proportions, or in percent of full scale. For example, a system has 12-bit resolution, one part in 4,096 resolutions, and 0.0244 percent of full scale.

·          RS232
It’s a standard for serial communications found in many data acquisition systems. RS232 is the most common serial communication, however, it is somewhat limited in that it only supports communication to one device connected to the bus at a time and it only supports transmission distances up to 50 feet.

·         RS485
It’s a standard for serial communications found in many data acquisition systems. RS485 is not as popular as RS232, however, it is more flexible in that it supports communication to more than one device on the bus at a time and supports transmission distances of approximately 5,000 feet.

• Sample Rate
  The speed at which a data acquisition system collects data. The speed is normally expressed in samples per second. For multi-channel data acquisition devices the sample rate is typically given as the speed of the analog-to-digital converter (A/D). To obtain individual channel sample rate, you need to divide the speed of the A/D by the number of channels being sampled.

• Single-ended Input (SE):
  Refers to the way a signal is wired to a data acquisition device. In single-ended wiring, each analog input has a unique high connection but all channels share a common ground connection. Data acquisition devices have either single-ended or differential inputs. Many support both configurations.

With the progress in technology data acquisition has become more advanced and reliable have come all the way from using simple devices to highly sophisticated computer systems and has proved to be the greatest engineering marvel in achieving data precision.

Article Tags: Data Acquisition, Acquisition Systems, Many Data

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