View A Video on Data Acquisition Systems - A Quick Introduction
Abbreviated DAS, data acquisition systems are both accessed and controlled by data acquisition software programs that utilize a wide range of general-purpose programming languages including Java, Pascal, Lisp and BASIC. Through the utilization of general-purpose programming, instead of industry or application-specific, data acquisition systems are able to be beneficial for a broad spectrum of industries including: medical, for the acquisition of clinical trial data by means such as central web based systems and local electronic data capture systems; industrial, to acquire data through methods such as chart recorders and PC-based systems; aerospace, for the acquisition of data by means including flight data acquisition units and structural dynamics test systems; and wastewater, in order to collect data for information regarding the toxicity of the wastewater and the effectiveness of the treatment.
There are many different components that can be utilized in the manufacturing of data acquisition systems, some of which are essential while others are simply advantageous in certain applications. Some of the essential components include sensors, signal conditioning circuitry and analog-to-digital converters. The sensors are necessary in data aquisition systems because they are the means of conversion of the physical data to the digital values. The signal conditioning circuitry, or signal conditioner, is necessary because it is also a means of conversion. However, instead of functioning in the same capacity as sensors, the signal conditioning circuitry is used to convert the signals from the sensors into a form that is more readily able to be converted into digital values. Lastly, analog-to-digital converters are an essential component of data acquisition systems because they are utilized to finally fully convert the signal after it has been transformed by the signal conditioning circuitry into digital values. Some of the more common uses of data acquisition systems include testing of all kinds for applications such as field studies, troubleshooting and research. Along with monitoring and making appropriate adjustments for processes, manufacturers can test all types of technical products using data acquisition systems.
A variety of components, devices and types of data acquisition systems are available to suit many applications. Some of the more common data acquisition devices include data loggers, temperature recorders and data acquisition cards. Data loggers, also known as data recorders, are defined as being any device with the ability of storing data. Some examples of specific data logging equipment include plug-in boards and serial communication systems. Although they are able to be used as part of a data acquisition system, data loggers are more commonly utilized separately and can even operate without the requirement of a computer. A more specific type of data logger, temperature recorders are utilized for the measurement of the physical phenomena of temperature, which is defined as the degree of either hot or cold of an environment. Temperature recorders can be mechanical, analog or digital, and once converted the information is then downloaded to a computer for usage in applications such as laboratory research and particularly weather stations in order to monitor meteorological conditions. Lastly, data acquisition cards refer to electronic hardware that must be physically plugged into a computer. DAQ hardware is used as an interface between the signal and a computer and the majority must be connected to a computer in order to run, although a small number are able to operate independently.
In addition to a variety of devices and components, there is a broad range of methods in which data acquisition can be achieved. Two common methods in industrial applications are personal computer (PC) data acquisition and universal serial bus (USB) data acquisition. The method of PC data acquisition refers to the vast majority of data acquisition systems and devices that require some sort of connection to a host computer in order to function and properly download the collected information. In fact, there are many types of data acquisition devices that plug directly into the host computer in order to function. One example of this type of data acquisition device is one that uses USB data acquisition. The definition of a USB device is a serial bus that has become standard for connecting and establishing communication between data acquisition devices and a host controller, which is typically a computer. USB data acquisition offers several advantages for DAQ systems including the ability to provide power to peripheral devices as well as offering a higher bandwidth which the capability of reaching 12 Mbits/s. Since USB devices are used in order to supply power, only one cable is required to link the data acquisition device to the computer, which will likely feature at minimum one USB port.
Data Acquisition Systems Types
- DAQ is an abbreviation for data acquisition.
- is the process in which electric signals from various devices are converted into a digital form that can be analyzed.
- Data acquisition cards are a form of data acquisition (DAQ)
hardware used to interface between a signal and a type of personal
computer (PC) such as a desktop, PC-compatible industrial computer or
an Apple Macintosh computer.
- Data acquisition software is designed to process, record, and analyze information received from various sensors and instruments.
- Data aquisition is the sampling of actual physical conditions such as property or
phenomena, which can include things such as light intensity, fluid
flow, gas pressure, temperature and force.
- are acquisition systems that store information from various devices.
- Data logging is the process of storing data that can occur in a variety of instruments and devices.
- receive and analyze information.
- enables computers to recognize and process signals received from monitoring devices.
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need a computer to operate. These devices are programmable and allow
the user to choose the different interval readings.
-
are stand-alone instruments that do not require computer operation and
print the measurements directly on a chart.
- PC data acquisition is a method of data acquisition that utilizes a personal computer (PC)
as the device to which the signals are converted to digital values for
further manipulation.
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are used to measure and record the pressure of a particular environment.
- Signal conditioners are data acquisition devices that are used to convert one type of electronic signal,
typically analog, to another type of electronic signal, which is almost
always digital.
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are a specific kind of data logger that record temperature and sometimes
humidity. Many of these devices are highly compact and can monitor conditions
inside packages; they also monitor the temperatures of facilities that
require regulated environments.
- USB data acquisition is a method of converting analog waveforms into digital values that can
be used for processing by means of a universal serial bus (USB).
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are very small and remote-controlled, and scan data by lasers. These
models are the latest technology in data acquisition systems.
Data Acquisition System Terms
- The sum of all factors
of error in a data acquisition device.
- The false reading
of high-frequency signals as lower-frequency signals. These readings are
expected errors from the discrete calculations with sampling devices like
analog-to-digital (A/D) converters.
- An apparatus
that attenuates the content of signals outside the preferred bandwidth
and comes before the analog-to-digital converter (ADC) in instrumentation
designs, which, in theory, permits the frequencies only in the pass band
to be sampled with the ADC.
- A signal that has a
value somewhere between two extremes and can constantly change.
- The procedure of converting
analog signals into a digital value or signal that is then able to be
stored on a computer.
- Transmission of data between receiving and transmitting
mechanisms in the form of zeros and ones. For correct data interpretation,
the receiving data needs to start at the appropriate location of the sequence.
- Protocol of data transmission for flood warning systems.
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- The process of adjusting a device to increase its accuracy.
- The required
voltage range as related to the datalogger ground into which both inputs
of a differential calculation must fall in order to make a differential
measurement.
- Receiving data
from an RTU, datalogger or field recording apparatus. This process is
done locally or remotely, depending on the data retrieval peripheral.
- An input channel configuration consisting of
two signal wires coupled with each input signal, one wire for input and
one for return signals. The measurement is the variation of voltage between
the wires.
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Analog measurements that measure the voltage between two inputs. Differential
measurements are able to reject noise better than single-ended calculations,
and can purge errors from differences in ground potential between the
sensors and the datalogger.
- Input/output
ports that sense status, read SDM peripherals or SDI-12 sensors and maintain
external devices.
- The electrical
current or voltage used with
transducers.
-
The use of a peripheral device to change a sensor's signal so another
non-compatible device is able to read the signal. Signal conditioning
mechanisms can be simple or complex.
- The frequent or periodic displacement of a signal away
from its intended location.
- A temporary storage location for information that has yet
to be processed or has not yet been transmitted.
- The lowest vital number at which a measurement is determined.
- The pace of measurements.
- Procedure of calculating a signal's value at discrete
time points.
- Amount of times per second that an analog signal
is measured as A/D conversion occurs.
- A measure of the minimum amount of change in a signal
that an instrument can detect.
- A device that responds
to a physical stimulus and generates an electrical signal or alters an
electrical property, such as resistance. The stimuli can be things like
light, sound, heat, pressure and motion.
- System that correlates redundant data storage with
measurement regulation, typically for regulating a manufacturing process.
Water treatment plants generally use SCADA systems.
- A sensor that converts
energy into readable electrical signals, which data loggers measure and
record. Examples of these include thermocouples
and strain gauges.
