Industries Information

Data loggers and data recorders acquire digital data from sensors and other signals. They are primarily used to store data for subsequent downloads to a host PC, but may also include real-time features such as monitors and alarms. Important specifications to consider when searching for data loggers and data recorders include differential analog input channels, digital I/O channels, sampling frequency, resolution, and accuracy.  Differential channels use the difference between two signals as an input; common mode is filtered out. In some systems, differential inputs are combinations of two single-ended inputs; in this case, twice the number of differential channels would be available as single-ended inputs.  Digital or discrete channels are used for low-level on-off signals used in applications such as communication, user interface, or control.  Sampling frequency is the frequency of the analog signal sampling and conversion to a digital value.  Resolution refers to the degree of fineness of the digital word representing the analog value. A ten-bit number contains 210, or 1024, increments. A 0-10V signal could therefore be resolved into approximately 0.01V increments. A 12-bit representation would be in 212 (4096) increments, or divisions of 0.0024V for the same signal. Each additional bit doubles the resolution, and one bit is required for the polarity (sign) of a number.  Data loggers and data recorders accuracy depends on the signal conditioning linearity, hysteresis, temperature considerations, etc. It is represented here as percent full scale of measurement range.

Common form factor for data loggers and data recorders include IC or board mount, circuit board, panel or chassis mount, modular bay or slot system, rack mount, DIN rail, and stand-alone.  Applications include general lab or industrial, environmental, vehicular, marine, aerospace or military, seismic or geotechnical, weather or meteorology, and medical or biomedical.  Common signal inputs available for data loggers and data recorders include DC voltage, DC current, AC voltage, AC current, frequency, and charge.  Sensor inputs include accelerometer, thermocouple, thermistor, RTD, strain gauge or bridge, and LVDT or RVDT.  Specialized inputs include encoder, counter or tachometer, timer or clock, and relay or switch.  Transducers and excitation are also important to consider when searching for data acquisition.  Many data loggers and data recorders have integral sensors or transducers.  These sensors can have voltage or current excitation.  Common outputs for data acquisition products include voltage output, current output, frequency output, timer or counter output, relay output, and resistance or potentiometer output.

Considering the user interfaces available is important when searching for data loggers and data recorders.  User interfaces available include no display, front panel and display, touch screens, hand-held or remote programmers, and computer programmable.  Host connection choices include direct backplane interface, RS232, RS422, ST485, USB, IEEE 1394, GPIB, SCSI, TTL, parallel, Ethernet, modem, and radio or telemetry.  The transmission rate of data is important to consider.  Many data loggers and data recorders are web enabled for web addressing.  Additional specifications to consider when searching for data acquisition systems and instruments include application software, memory and storage, network specifications, and environmental parameters.

Data acquisition is the processing of multiple electrical or electronic inputs from devices such as sensors, timers, relays, and solid-state circuits for the purpose of monitoring, analyzing and/or controlling systems and processes.  Data acquisition instrument types include computer boards, instruments or systems, dataloggers or recorders, chart recorders, input modules, output modules, and I/O modules.  Computer boards are self-contained printed circuit board with full data acquisition functionality; typically plugs into a backplane or motherboard, or otherwise interfaces directly with a computer bus.  Instruments or systems are fully packaged with input and output, user interface, communications capability, etc. They may include integral sensors.  Data loggers and data recorders are data acquisition units with instrument functionality with specific capability for data storage. May be for general purpose or application-specific data acquisition.  Chart recorders generate real-time plots, graphs or other visualizations of data.  Input modules are devices (module or card) configured to accept input of sensors, timers, switches, amplifiers, transistors, etc. for use in the data acquisition system.   Output modules are devices with specific functionality for output of amplified, conditioned, or digitized signal.  I/O modules have both input and output functionality. Digital or discrete I/O includes on-off signals used in communication, user interface, or control.

Common form factor for data acquisition devices include IC or board mount, circuit board, panel or chassis mount, modular bay or slot system, rack mount, DIN rail, and stand-alone.  Common device specifications to consider when searching for data acquisition products include differential analog input channels, digital I/O channels, sampling frequency, resolution and accuracy.  Common signal inputs available for data acquisition products include DC voltage, DC current, AC voltage, AC current, frequency, and charge.  Sensor inputs include accelerometer, thermocouple, thermistor, RTD, strain gauge or bridge, and LVDT or RVDT.  Specialized inputs include encoder, counter or tachometer, timer or clock, and relay or switch.  Transducers and excitation are also important to consider when searching for data acquisition.  Many products have integral sensors or transducers.  These sensors can have voltage or current excitation.  Common outputs for data acquisition products include voltage output, current output, frequency output, timer or counter output, relay output, and resistance or potentiometer output.

Considering the user interfaces available is important when searching for data acquisition products.  User interfaces available include no display, front panel and display, touch screens, hand-held or remote programmers, and computer programmable.  Host connection choices include direct backplane interface, RS232, RS422, ST485, USB, IEEE 1394, GPIB, SCSI, TTL, parallel, Ethernet, modem, and radio or telemetry.  The transmission rate of data is important to consider.  Many products are web enabled for web addressing.  Common applications for data acquisition products include general lab or industrial, environmental, vehicular, marine, aerospace or military, seismic or geotechnical, weather or meteorology, and medical or biomedical.  Additional specifications to consider when searching for data acquisition products include application software, memory and storage, network specifications, filter specifications, amplifier specifications, and environmental parameters.

Paper recording charts and consumables consist of circular charts, strip charts, markers, fanfolds, sheets, pens, and pen arms used in chart and strip recording instruments. A chart recorder is an instrument used to record various process and electrical signals. The paper is passed under a pen and the pen is deflected in proportion to the signal. The result is a graph or chart of the data. There are many types of paper recording charts. Examples include circular charts and strip charts. Circular charts are used in circular chart recorders which record data in a circular format. The paper is spun beneath one or more pens. The pens are deflected in proportion to the varying signal resulting in a circular chart. Strip charts are used in strip chart recorders which consist of a roll or strip of paper that is passed linearly beneath one or more pens. As the signal changes the pens deflect, producing the resultant chart. Paper recording consumables refers to various other instruments and materials, such as sheets, paper, and pens, which are used in a chart recorder. Other paper recording charts and consumables are commonly available.

Paper recording charts and consumables are available in various sizes according to the required specifications. Chart recording paper is defined by its part number, which determines its size. Various sheets of paper are used for making a particular type of chart. A specialty paper called strip chart paper is used for making strip charts, which are used with strip recorders. An industrial recording chart is used with an industrial recorder. Generally, industrial recorders have the recording width of 100mm and 180mm. Recorder pens are an important paper recording consumable used in chart recorders. Recorder pens are used to write in style and record the data. Recorder pens may have fiber tip or micro tip. Paper recording charts and consumables are manufactured to meet most industry specifications.

Paper recording charts and consumables are used in many applications. Examples include its use in recording data of a given environment, such as refrigeration, air conditioning, storage, transport, and workplace or home monitoring. Paper recording charts and consumables should adhere to various standards specified by American National Standards Institute (ANSI) and International Standards Organization (ISO) standards.

Chart recorders and strip charts are data acquisition tools used to generate a plot, graph or other visualization of data versus time. Common applications include temperature and humidity measurements, chromatography, spectroscopy graphs, and plots of the output of a wide range of other lab and test equipment.

Chart recorders typically output data in one of four common formats.  These include circular x-y plotter, strip chart, or paperless, video graphing.  Circular charts rotate uniformly while variable is plotted radially. Advantages include relatively compact size and simplicity of operation. Revolution time may span from minutes to days.  In an X-Y plotter two selectable variables are plotted against each other in rectilinear coordinates. The paper source is often a standard size sheet, but can also be a roll or drum. Plotted variables may include mathematical functions of data input.  Strip charts plot variables with regard to time, as the paper strip advances uniformly through the plotter. Strip frequently comes off a roll for space conservation.  In a paperless or video graphing system the plot is displayed on video screen; scaling and mathematical functions possible.  Chart recorders and strip charts can produce multiple plots simultaneously.

Important data acquisition specifications for strip charts and chart recorders are differential analog input channels, digital I/O channels, sampling frequency, resolution, and accuracy.  Differential channels use the difference between two signals as an input; common mode is filtered out. In some systems, differential inputs are combinations of two single-ended inputs; in this case, twice the number of differential channels would be available as single-ended inputs.  Digital or discrete channels are used for low-level on-off signals used in applications such as communication, user interface, or control.  The sampling frequency is the frequency of analog signal sampling and conversion to a digital value.  Resolution refers to the degree of fineness of the digital word representing the analog value. A ten-bit number contains 210, or 1024, increments. A 0-10V signal could therefore be resolved into approximately 0.01V increments. A 12-bit representation would be in 212 (4096) increments, or divisions of 0.0024V for the same signal. Each additional bit doubles the resolution, and one bit is required for the polarity (sign) of a number.  Accuracy depends on the signal conditioning linearity, hysteresis, temperature considerations, etc. It is represented here as percent full scale of measurement range.  Some chart recorders and strip charts come equipped with recorder or datalogger, which has instrument functionality with specific capability for data storage. May be for general purpose or application-specific data acquisition.

Common signal inputs for strip charts and chart recorders are DC voltage, DC current, AC voltage, AC current, frequency and charge.  Typical sensor inputs for chart recorders and strip charts are accelerometers, thermocouples, thermistors, RTDs, strain gauges or bridges, and LVDTs and RVDTs.  Specialized inputs may include encoders, counters or tachometers, timers or clocks, and relays or switches.

Features common to chart recorders and strip charts include transducers and excitation supplies, auxiliary outputs, user interfaces, communications with computers, application software and memory and storage functions.