instruNet is a family of data acquisition hardware that provides ten's of microVolts of absolute accuracy instead of ten's of milliVolts, at the same cost, and at the same throughput rates as the typical general purpose data acquisition board. It does this with a completely different topology where the analog electronics are put close to the sensor in electrically quiet boxes outside of the computer, and the noisy digital electronics are left inside the computer.
The external boxes, shown above, contain signal conditioning amplifiers for each channel, and can therefore directly attach to sensors such as thermocouples, RTD's, strain gauges, resistance sources, current sources, and voltage sources; and return engineering units (e.g. "Volts","Amps"). For a larger picture, click here.
At the heart of the system is a PCMCIA or PCI bus controller board, shown to the right, that plugs into a Windows 95/98/Me/NT/2K/XP or Macintosh computer (except the PCMCIA card on Win NT). For a larger picture, click here. The controllers contain a 32bit microprocessor with 256KB of RAM that manages the external network of devices. All real-time tasks are off-loaded to this processor, therefore the host computer is not burdened with real-time issues. The instruNet 100 Network Device, pictured at thetop of this page (the long black box with BNC connectors), provides:
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The instruNet 100 includes 44 screw terminals, or optionally 16 BNC's for analog inputs. The controller's themselves provide 10 counter/timer channels that each can function as a digital input bit, a digital output bit, a clockoutput channel, or a period measurement input channel.
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Why is instruNet Better than traditional Data Acquisition Boards? One word. Accuracy. instruNet provides ten's of microVolts of absolute accuracy instead of ten's of milliVolts. How does instruNet deliver better Accuracy? Several reasons:
How does this increased accuracy help me? Primarily, this enables one to attach Directly to Thermocouples, Thermistors, RTDs, Strain Gages, Load Cells, Potentiometers, Accelerometers, Voltage Sources, Resistance Sources, & Current Sources. Which means one does not need to add expensive signal conditioning amplifiers. Where is the proof that instruNet is more accurate? The primary proof is in the Specifications. instruNet specifies Absolute Accuracy whereas traditional data acquisition boards do not. An example of an absolute accuracy specification is to say a measuring system will always measure a voltage accurate to +-1mV on a +-5V range. Traditional boards don't do this because the sum of all errors, including cable cross-talk and ground loops, are not pretty. Other Advantages
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For more information, please see:
instruNet includes the following FREE application software:
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instruNet is Compatible with the following application software. To learn more, one can view the Application Software Notes.
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instruNet includes FREE interfaces for the following development environments. To learn more, one can view the instruNet Manual, view the Programming Application Notes, or download the Interfaces themselves.
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instruNet World Software (not +), a FREE application program, manages, monitors and operates the instruNet network. Additionally, it digitizes long continuous waveforms, spools them to disk, views incoming waveforms in real-time and then allows post acquisition viewing -- much like an oscilloscope or strip chart recorder.
Waveforms are recorded in one long continuous stream (strip chart mode); or they are digitized in short segments where each segment begins after a specified trigger event (oscilloscope mode). Any one of the i100xx analog or digital input channels can be used as a trigger. Data is either placed into RAM memory, a file on disk, or is deleted after being plotted. One uses the Setup dialog box to set the sample rate (i.e. points-digitized-per-second-per-channel) and number of points digitized; and uses the Network page to select which channels are digitized. After setting up the system; one can press the Network Save button to save the setup, press the Start button to start digitizing, press the Stop button to stop it, press the Record Save button to save waves in RAM to disk (post-acquisition), and press the Open button to load waves from disk for viewing.
A spreadsheet like environment, illustrated below, is used to set and view channel parameters such as sensor type (e.g. thermocouple, strain gage), integration time (i.e. how long the A/D reads a channel to get one value, which is used to reduce noise), analog filter options, and digital filter options (i.e. low pass, high pass, band pass, band stop). Each channel has its own row in the spreadsheet, with the various options in the columns. One clicks on an item to change it.
The instruNet World Test page enables one to test and view installed hardware, as illustrated below.
For more information on the FREE instruNet World software, please refer to the instruNet User's Manual chapters 2 and 5. For more information on the NOT free version of instruNet World (called "iW+"), which provides additional features, please click here.
VB Instrument implements a strip chart/oscilloscope recorder for 1 to 16 channels. It is similar to instruNet World software, yet is written in Visual Basic and the source code is included. You are welcome to modify it. For details, click here.
VB Scope implements a 2 channel strip chart recorder, XY Record, and Spectrum Analyzer. VB Scope is written in Visual Basic, source code included. For details, click here.
The Digitize Direct To Excel program, which requires iW+, populates an Excel (Version >= 8.0, Office >= 97) spreadsheet, shown below, while digitizing. For details, click here.
The instruNet network supports the digitizing of multiple channels at aggregate sample rates of 166ks/sec, where each channel can be digitized at it's own sample rate. Also, each channel can be independently digitally filtered with lowpass, high pass, band stop and band pass filters; where the filter specification for each channel is independently set in software.
Each channel also provides a programmable analog low pass filter and programmable A/D measurement integration time. The network can be hundreds of feet long and can support multiple hardware devices connected together in a daisy-chain configuration. Also, the start of digitizing can be triggered off of any channel. There are no jumpers or pots; the system automatically self-calibrates on power-up. Since instruNet is modular, it can easily be expanded as needs evolve. Also, one can easily move the network from one computer to another,since the various controllers (e.g. PCI, Pcmcia), and the software interface,are functionally identical.