INSTRUNET WORLD TUTORIAL
SOFTWARE > INSTRUNET WORLD SOFTWARE (iW) > TUTORIAL >

instruNet World software tutorial sections include:

Record Waveforms in 7 Easy Steps
Digitizing Directly to Excel
Working with VB Instrument
Working with VB Scope
Digitizing Analog Signals Into the Computer
The instruNet Data Tree
Explore Your World
Working with Sensors
Working with Calibration, Different Scales, and Mapping
Working with Digital Filters
Working with Voltage Output Channels
Working with Digital I/O Channels
Working with i200 Controller Digital Timer I/O Channels
Working with the i2x0 Controller, Time Since Reset Channel
Working with Multiple Controllers
Next Step

This is a step-by-step tutorial that shows the user how to navigate within the world of instruNet.  Controlling instruNet hardware can be done manually though the free instruNet World application program, or through the programming languages Visual Basic and C.  This document deals exclusively with the easy-to-use application program instruNet World application program.  instruNet World software allows you to set up and probe your network, record waveforms, save them to disk, load them from disk, and view them post acquisition.

This document focuses on the buttons at the top of the instruNet World pages, yet these functions can also be accessed in the menubar.  For documentation on the menubar and on instruNet World PLUS "iW+" (a version of instruNet World with more features), please click here.

Record Waveforms in 7 Easy Steps

This section explains how to record waveforms in several easy steps. 

1.      Install your hardware and software
If your instruNet World hardware and software is not installed, please install it now, as described here .

2.      Run the instruNet World application program.
Locate the instruNet world application program within the instruNet folder on your hard disk and then:

Windows: Double-click on "instruNet World Win32.exe", or run "Start > Programs > instruNet > instruNet World".
Macintosh: Double-click on the "instruNet World Mac" icon.

3.      Select the Network Page.
instruNet World offers several Pages: Record, Network, and Test.  Click on the Network tab at the bottom of the window to select the Network page.  The Network tab will inverse black to indicate the Network page is selected.

4.      Enable a Channel for digitizing.
A channel is enabled for digitizing by clicking on the small cell between the addr and ValueInput columns within the Network page, as illustrated below.  Once enabled, the channel will be digitized when the user presses the Start button on the Record page.  To disable a channel, one must click the digitize on/off cell again.  This digitize on/off cell is black or red when On, and white when Off.  Any number of channels can be selected for digitizing. 

Please enable two voltage input channels (e.g. "Ch1 Vin+" and "Ch4 Vin+" on the Model 100) for digitizing, as illustrated below.  Voltage input channels are typically labeled ChX Vin+ or ChX Vin-.  These work identically when doing single-ended voltage measurement (i.e. read a voltage between an input terminal and ground), and are used as a pair when doing differential voltage measurement (i.e. reading a voltage between 2 input channels).  If instruNet voltage input hardware is not installed, you will not be able to digitize.  Also, note that the contents of the Network page may vary depending on what is installed on your computer.

5.      Attach a signal source.
If possible, attach a signal source to at least one channel's hardware input terminal.  For example, one might attach a Function Generator output to the instruNet "Ch1 Vin+" input terminal, and the Function Generator's ground to the instruNet "AGND" terminal.  It is not necessary to connect a signal source to do the tutorial, however, the displayed waveforms are more interesting if a signal is applied; otherwise, you get a flat line at 0Volts.

6.      Select the Record Page.
Select the Record page by clicking on the Record tab at the base of the window, as illustrated below.

7.      Tell instruNet to start digitizing.
Click the Start button at the top of the window to tell instruNet to record and display channels that have been enabled for digitizing (e.g. "Ch1 Vin+").  You should see your waveforms move across the screen as they are digitized in real-time, as illustrated below.

8.      Tell instruNet to stop digitizing
Click the Stop button to stop the digitizing process. 

9.      Save your waveforms to disk
Click the Save button to save your waveforms to disk.  When the save dialog appears, type a name and choose a convenient location to save the data.  Saving does not specify a file name, but rather a folder name in which all acquired waveforms and a preferences file are saved. For example, if you digitized 2 waves and then clicked Save,  3 files would be stored in your: one named "instruNet.prf" that contains the Field settings, and two files that have the same name as the two channels, that contain the wave data.

10.    Record again
Click the Start button to start recording again, and then click the Stop button after a few moments.

11.    Load your saved waves from disk
Click the Open button to load in the previously saved waves from disk.  A File open dialog will appear, and it is here that you must select one of your previously saved files (e.g. "instruNet.prf", "Ch1 Vin+" or "Ch4 Vin+").  After your waves are loaded in, they should appear in their displays.

BACK TO TOP OF PAGE

Digitizing Directly to Excel

If you want to learn how to digitize in instruNet World, and then save a text file to be loaded by a spreadsheet program, post-acquisition, please ckick here.   If you want to digitize into a spreadsheet,  while data is being acquired, please consider the Direct To Excel program, described in detail here.  Note that Direct To Excel requires that an iW+ license be installed on your computer.

•   In order to run Direct To Excel, All of the following must be installed on your computer. If this is not the case, please proceed to the next section.

• Windows Excel version >= 8.0 (i.e. Microsoft Office >= 97)
• Windows >= 98 (not Windows 95, not Macintosh)
• iW+ license (see www.instrunet.com/plus for details)
• Windows .Net Framework (which is included with the instruNet software, and is included automatically on Windows >= XP computers)
• instruNet software >= 2.0 (7/1/2003), available at www.instrunet.com/d

If you are not sure these requirements have been satisfied, try running the Direct To Excel program, as described below, and if it runs ok, then you are probably ok.

•   Exit instruNet World and select under the Windows START menu: Programs / instruNet / Application Software / Direct To Excel  / Direct To Excel.exe.  This will run a program (shown below) written in Visual Basic; the source code of which is currently installed on your hard disk.  You are welcome to modify it.

•   Press the Channels button, select 2 channels for digitizing (i.e. click in small rectangle after channel address, it will turn red), and close the instruNet Network window.

•   Press the Start button and watch a new spreadsheet window appear and fill with instruNet data, as shown below.  When finished, you can save or delete the Excel spreadsheet file.

•   To learn more, please press the Help button or click here.

•   Close the Direct To Excel program by clicking in the upper right corner.

BACK TO TOP OF PAGE

Working with VB Instrument

•   We will now run a Windows program called "VB Instrument" that implements a strip chart/oscilloscope recorder for 1 to 16 channels.  It is similar to instruNet World, yet is written in Visual Basic and the source code is installed on your computer.  You are welcome to modify it.  If you are on a Macintosh, please proceed to the next section.

•   Exit any currently running instruNet software and select under the Windows START menu: Programs / instruNet / Application Software / VB Applications  / VB Instrument.exe. 

•   Press the Channels button, select 4 channels for digitizing (i.e. click in small rectangle after channel address, it will turn red), and close the instruNet Network window.

•   Press the Start button and watch the data appear in the window, as shown below.

•   To learn more, please press the Help button or click here.

•   Close the VB Instrument program by clicking in the upper right corner.

BACK TO TOP OF PAGE

Working with VB Scope

•   We will now run a similar Windows program (written in Visual Basic, source code included) called "VB Scope".  It implements a 2 channel strip chart recorder / oscilloscope, XY Record, and Spectrum Analyzer.  If you are on a Macintosh, please proceed to the next section.

•   Exit any currently running instruNet software and select under the Windows START menu: Programs / instruNet / Application Software / VB Applications  / VB Scope.exe. 

•   Press the Start button and watch the data appear in the window, as shown below.  Ch1 and Ch2 timewaves are shown in the left-most display, the frequency spectrum of Ch1 is shown in the upper-right display, and an XY plot of Ch1 and Ch4 are shown in the lower-right display.,

•   To learn more, please press the Help button or click here.

•   Close the VB Scope program by clicking in the upper right corner.

BACK TO TOP OF PAGE

Digitizing Analog Signals into the Computer

The Setup button at the top of the Record page opens a dialog box that effects the manner in which waves are recorded.

•   Click the Setup button to open the Setup dialog, as illustrated in Figure 2.1.

Figure 2.1  The Record Setup Dialog

The Setup dialog is used to set the base sample rate, the number of points to be acquired per Scan, the number of Scans to be acquired and the recording mode (i.e. oscilloscope or strip chart recorder).  All instruNet Networks are set up with one base sample rate (i.e. number of points digitized per second) and individual channels can have sample rates less than or equal to the base sample rate.  This allows, in effect, each channel to have its own sample rate.

The Sample Rate field sets the base sample rate in units of samples-per-second-per-channel.  The Pts Per Scan field determines the amount of data to be collected in each Scan.  The No. of Scans sets the number of Scans to be acquired.  The Scan Mode popup has three choices: Strip Chart, Oscilloscope, and Oscillo Queued.  Strip Chart is selected for continuous strip chart recorder mode and Oscilloscope or Oscillo Queued are selected for oscilloscope mode.  Refer to Oscilloscope or Strip Chart? for a full description of these modes.  

If the instruNet system reduces your sample rate to an unacceptable level, or your analog voltage data is too noisy, please see SAMPLE RATE VS. INTEGRATION VS. NOISE. 

instruNet Networks are self-configuring and on startup determine the maximum rate at which data can be transferred.  This rate is displayed after pressing the Timing button, in the Network BPS field, in units of bits per second.  4 million bits per seconds is the fastest, and 100Kbps is the slowest.  This rate slows down with networks that have many Devices and long network cables (i.e. >100ft).

•   Select Oscilloscope in the Scan Mode popup and set the Pts Per Scan field to 100.  100 points at 1000s/sec will take .1 seconds to acquire.  Leave the rest of the Dialog in its default settings, and click OK to return to the Record Page.

•   Click the Start button to begin digitizing.

Notice how 0.1 second long waveforms continuously appear on the screen, in a manner similar to an Oscilloscope.  Before, we were in Strip Chart mode where these segments were continuous with respect to each other.  We are now in Oscilloscope mode.  To learn much more about digitizing, please refer to the Record Page Reference.

•   Click the Stop button to stop digitizing, and then click on the top display's channel name label at the right edge of the display.  The Display dialog will open.  Choose General in the Settings popup.  Enter the value 20 in the % samp rate field as shown above, and press OK.

This will cause the top channel to be digitized at 20% of the master sample rate, or 200s/sec.  The channel in the lower displays will continue to run at the master sample rate of 1000s/sec.

•   Click the Start button to begin digitizing, and then click Stop after a few moments.

Notice how the wave in the top display contains fewer points, due to its reduced sample rate, as illustrated to the right.

•   Click the Setup button at the top of the Record page, and then click the Trigger button to open the Trigger dialog, as shown in Figure 2.2.

Trigger Modes
instruNet World allows triggering from any channel on either a low-to-high or high-to-low transition through a threshold value.  The threshold is specified in the Thresh EU field, and the trigger direction is specified in the Slope field (i.e. low-to-high, or high-to-low).  The channel to trigger from is specified by its network address in the Trig Net#,Trig Dev#, Trig Mod# and Trig Chan# fields.

Three trigger types are allowed, as specified in the Trigger field: Off, Auto and Norm.  If Off is selected, data acquisition begins as soon as the Start button is pressed in the Record Page.  If Auto is selected, data acquisition begins after the trigger criteria is met, but if the trigger condition is not met within a second or so, the recording begins anyway.  If Norm is selected, instruNet waits until the trigger condition is met, indefinitely of necessary.

Fig 2.2 The Trigger Dialog

•   Enter the address of a channel to trigger from into the Trig Net#, Trig Dev#, Trig Mod# and Trig Chan# fields.  If you are not sure of a channel's address, go back to the Network Page and look at the Channel and Addr column for the channel you want to trigger from.  The address for the two channels shown in the above figure would be {1,1,1,1} and {1,1,1,4}.  For example, if you wanted to trigger from channel Ch4 Vin+, you would enter the following values:  1 into Trig Net #, 1 into Trig Dev#, 1 into Trig Mod#, and 4 into Trig Chan#.

•   Select Auto in the Trigger popup, type a reasonable threshold voltage into the Threshold EU field (e.g. 1V) and then select Rising or Falling in the Slope popup.  Click OK to exit the Trigger Dialog, click OK to exit the Setup  Dialog and then click the Start button to begin recording.

The waveforms should appear on the screen, with the beginning of each Scan synchronized to the trigger event.  If the signal applied to the trigger channel does not periodically cross the threshold voltage, Auto trigger will digitize anyway every second or so.

•   Press Stop when you are done acquiring.

To learn more about Triggering, please refer to Trigger Reference.

•   Click the Setup button at the top of the Record page to open the Record Setup dialog, as shown in Figure 2.1.           

Display Options
The Horiz Scale field sets the display horizontal scale in seconds-per-division.  If set to Auto, instruNet picks a horizontal scale that is appropriate based on the sample rate and number of data points being acquired.  This popup is also provided at the lower right of the Record page when iW+ is installed.

The Plot popup is used to set the drawing mode to plot Dots or Lines (i.e. light one pixel for each data point, or connect these data points with lines), and the Grid popup (accessed by pressing the Record button in Setup dialog) selects whether or not to overlay a grid on each display.

Viewing Many Channels
The Disp Height field sets the minimum height of each display in the Record page, in pixels.  If the number of waveforms being digitized is greater than the available space on the screen, only a subset are displayed, and the vertical scrollbar selects that set.  For example, if the Record page is 1000 pixels high, the Disp Height field is 100, and one is digitizing 512 channels (the maximum amount); only 20 would be shown at one time, and the vertical scrollbar would select that set of 20.  In another example, if the window was 640 pixels high, one was digitizing 32 channels, and one wanted to see all channels at once; one would need to set the Disp Height field to 20 (i.e. 20 pixels * 32 channels = 640pixels).

Another technique is to hide individual displays by setting the Display View field to Hide for each channel that you do not want a Display in the Record page.  One does this by opening the channel options dialog for each channel you want to hide, select the Display setting, and then set the Display View field to Hide.  If you want to view channels numerically, then please consider Panel Meters, which are only available in iW+ (described at www.instrunet.com/plus).

Time Of Day or Relative Time
The Horizontal Label field allows one to show either Relative time or Time of Day in the Record page horizontal timescale, as illustrated below.  Relative time shows the number of seconds since starting the digitization at 0 seconds.  Time of Day shows the time of day, as known by the computer's clock. For example, if you start digitizing at 1:05 am on Feb 1, 2003, it will show "0117, 2/1/03" 12 minutes later.  Post-Acquisition, one can change this field to view the data with either timescale format.  Displaying Time of Day requires instruNet World PLUS (iW+).

Time Relative to start of digitization, left edge corresponds to 0 secs

Time of Day, e.g. first grid corresponds to May 27, 2003, 3:51pm + 15 seconds

Working with Files and Data
The Digitize Into popup has 2 primary settings: To Ram Buffer, which saves digitized data into RAM; and To File, which digitizes data directly to disk.  If Digitize Into is set to To File, instruNet automatically prompts the user for a folder name every time a recording session is initiated with the Start button.  The waveforms are then saved to this folder while they are recorded.  One can then scroll through these long disk-based waveforms (e.g. 20M points per channel) via the horizontal scrollbar.  Any waves saved to disk using the To File option can be opened and scrolled through with the Record Page's Open button.

The File Type field determines the file format for the saved data, and is set to one of Binary, Binary Merge, Text, or Text Merge.  For a detailed description of each format, please see File Types. If you want to save data to a spreadsheet program, post-acquisition, please click here.

•   Select Lines in the Plot popup, select Off in the Grid popup, select "Strip Chart" in the Scan Mode popup and, set the Pts per Scan field to 10000 to set the buffer size of an intermediate RAM buffer that holds data before it is sent to disk (10000 points at 1Ks/sec is a comfortable size).  Set the Digitize Into popup to "To File", and select 0.5 secs/div in the Horiz Scale popup.  Click OK to exit the dialog.  Click Start to begin recording.  When the File save dialog appears, type a folder name and select a location for the waveforms that are about to be "spooled" to disk.

•   After a minute or so, press the Stop button to stop digitizing.  Scroll through your waveforms via the horizontal scrollbar.  Notice that the computer goes to your hard disk periodically to automatically load in information from disk.

•   Try various options and settings to gain some familiarity with the wonder world of instruNet World.  Some things to try are listed below:

• Press the Start button to start recording again.
• Press the Save button to save the digitized waves to disk (if they are RAM based).
• Press the Open button to load previously recorded waveforms from disk.
• Press the Setup button to adjust the sample rate and number of points that are digitized when the Start button is pressed.
• Press the Trigger button within the Setup Dialog to adjust the trigger options.
• Press the Network tab to select the Network page, and then turn on other channels for digitizing by clicking on their digitize on/off cells.

Digitize directly into RAM memory or a File on Disk?
For a discussion of this topic, please click here.

The InstruNet Data Tree

instruNet stores field settings in a hierarchical data tree illustrated in figure 2.4

Figure 2.4 Network Hierarchy for instruNet

To access a piece of information, you must supply an address within this data tree.  This address consists of 6 parameters, as described below:

Network Number     
If 0, this refers to the Driver itself (e.g. plot lines or dots in the Record displays); otherwise, this number refers to an instruNet Controller board, where the first board found in the computer is designated Network Number 1, the 2nd board found is Network #2, etc.

Device Number       
This refers to hardware devices (e.g. Model 100) attached to an instruNet Controller board, where the hardware Device closest to the Controller is Device #1, the next device is Device #2, etc.

Module Number      
This refers to the module within a hardware device.  At this time, all Devices have only 1 module that is referred to as Module #1.

Channel Number     
This refers to a specific channel in a hardware device.  Each channel typically corresponds to a physical wire somewhere, such as a voltage input, voltage output, digital input, or digital output.  For example, in the Model 100, the screw terminal marked "Ch1 Vin+" is Channel #1 and is a voltage input.

Setting Number       
Each channel includes different Settings areas such as: lowpass filter settings, highpass filters settings, Hardware settings, etc.  It is here that one selects a settings group (e.g. Lowpass Filter fields have a Settings Number of -9).

Field Number          
This is the Field Number {1..8} within a settings group.  For example, in the Lowpass Filter settings group, the cut-off frequency in Hertz is stored in Field #5.

The instruNet World user navigates within this data tree via the Probe dialog, described in the next discussion.  instruNet World does not require the user to know about Setting numbers and Field numbers since all items are defined using popups and edit fields.  The programmer, on the other hand, must supply 6 numbers to a subroutine to read and write to any field on the instruNet data tree. 

The Network page shows the current Field settings for each channel in a tabular (i.e. spreadsheet) format, and is also a useful tool for navigating around the instruNet data tree.  The data tree maintains any changes you make until you Reset the network via the Reset button, reset the computer, or load in new setting from disk via the Restore or Open buttons at the top of the Network page.  In many cases, a user will set the fields as needed, stored them to disk, and then reload them when instruNet world is first opened.

BACK TO TOP OF PAGE

Explore Your World

•   Exit all instruNet software and run instruNet World.

•   Select the Network page by pressing the Network tab at the bottom of the window.

•   Press the Reset button at the top of the window to reset all Fields in the Data Tree.  Press OK when a dialog asks for confirmation.

Figure 2.5 illustrates how information is organized in the Network page.  The channels that are displayed on your computer will vary depending on what hardware is installed; therefore, don't worry if your screen is a little different from the Figures.

Figure 2.5  Partial view of the Network Page

The Network Page
Each row in the Network page corresponds to an input or output channel, which is often associated with a physical sensor in the real world.  Each channel has a {Network, Module, Device, Channel} address both within the software data tree and the physical outside world.  This address is shown in the first 4 columns of the Network page.  The first column indicates the Channel name and number.  For example, "Ch1 Vin1+" is Channel #1 and the channel name is "Ch1 Vin1+".  Columns #2 through #4 indicate the channel's Network #, Device # and Module #, which correspond to a physical address. 

The column labeled "Value Input" depicts the current real-time value (input or output) of the channel, in engineering units.  All columns to the right of the Value Input column are Fields that specify the type of signal connected to the channel and how it is being read.  The horizontal and vertical scroll bars are used to move around and make changes to the tables contents.  To change a Field's setting, one can click on its cell and then change its value.  For example, to change the name of channel Ch1 Vin1+, one would click on the "Ch1 Vin1+" cell.

•   Click on any cell in the Units Label column to open the Probe dialog, as shown in figure 2.6.

Figure 2.6 The Probe Dialog

The Channel Setup Probe Dialog
Using the Probe dialog, any Field within the instruNet Data Tree can be viewed or modified.  The upper-most 4 popup menus specify a channel address (i.e. Network, Device, Module, Channel), the Settings popup specifies a Setting group (e.g. General, Lowpass Filter, Highpass Filter, etc), and the Settings area shows between 1 to 8 Fields depending on the Settings group selected. 

For example, in Figure 2.6, we are viewing the General settings for channel Ch1 Vin+, which is physically connected to the 1st Device (a Model 100) attached to the 1st Controller (i.e. Network), which is plugged into computer slot #12.  The General settings group contains 4 Fields: Value Input, Units Label, User Name, and % Sample Rate. 

The Value Input field shows the real-time, current value, of the channel, UnitsLabel is the displayed label for the channel's value (e.g. "Volts", "Amps", "C"), UserName is the user's name for the channel (e.g. "Temp 1", "Pressure 2", etc), and %SampleRate is the speed, as a fraction of the Master Sample Rate, that the channel is digitized (e.g. 50% would mean the channel is digitized at one-half the sample rate specified in the master Setup dialog).  The small display at the bottom of the Probe dialog shows a plot of the current real-time value of the Channel.

•   Click on the Units Label field and change "Volts" to "Amps".  Click OK to exit the Probe dialog. The clicked on cell should be update to "Amps", as shown in figure 2.7.  

Figure 2.7 Edited cell within the Network page

•   Scroll through the Fields of the Network page using the horizontal scroll bar at the base of the window. 

Notice that the first 5 columns remain fixed, while the cells to the right of Column #5 shift left and right with the horizontal scrollbar.  You can scroll through, and view, all Fields for all Channels in this manner.  Figure 2.8 shows the Network Page for Ch1 Vin+ after scrolling a little to the right.

Figure 2.8 Network Page scrolled horizontally to view the Ro & Rshunt Fields

•   Scroll horizontally to the left edge so that "Value Input" is in Column #6 and then scroll vertically until an input channels is no longer in the top row.  For example, in Figure 2.9, a Voltage Output channel is in the top row.

Notice that the title to Column #6 changed from Value Input to Value Output.  This is because the titles are optimized for the one channel in the top row.

Figure 2.9 Network Page scrolled vertically to view the title for voltage outputs.

•   Vertically scroll to the top of the table and then click on the net cell of the first row. (it should contain a 1)  This will cause the Probe dialog to open and to display the clicked on cell.

Channel Addresses
The upper region of the Probe Dialog, shown in Figure 2.6, is used to select a Channel's address (i.e. Network Number, Device Number, Module Number, and Channel Number).  

The Device popup menu lists the network Devices that are attached to the Controller specified in the Network popup menu.  When you select a Controller in the Network popup, all devices attached to it appear in the Device popup.  In the figure shown to the right, only one network device is attached to the Controller in Slot 14 and it appears as the second item in the popup. 
It is a Model 100 and is designated Device #1 (1 #100).  The Controller itself is a Device (Device #0) and appears as the first item in the Device popup.  The Controller contains Fields that are specific to the controller, such as the network sample rate, or the value of a digital output on the Controller's Digital I/O Connector.

The Module popup lists all Modules in the currently selected {Network, Device}.  Most Devices only have 1 module, as shown to the right.

The Channel popup lists all analog and digital I/O channels in the currently selected {Network, Device, Module}.  The illustration to the right shows 3 channels, 2 of which are voltage inputs, and the 3rd which is a voltage output.

•   Explore your instruNet world via the 4 Channel Address popup menus at the top of the Probe dialog, and the Settings popup menu.  Press OK when you are done exploring.

Saving & Loading Network Settings
All instruNet Fields (i.e. all the cells in the Network page) are saved to disk and loaded from disk with the press of a button.  When a configuration is saved, all information including items such as trigger conditions, sample rates and channel units are stored.  Waveform data is not stored at this time, but can be saved by pressing the Save button in the Record page.  When a configuration is loaded, all items are restored to their previously saved condition.  This means that instruNet configurations for specific experiments only need to be set up once.  And once a configuration is loaded, it can be changed and then saved again if needed, possibly in a different file.

•   Select the Network page by clicking the Network tab.

The first two buttons at the top of the Network Page, Restore and Store, work as a pair.  Clicking the Store button saves the current network settings to a preferences file within your operating system folder.  Clicking Restore loads in this file.  File open and save dialogs do not appear, since the Fields are always saved to the same file (i.e. a file with the same name).  Obviously, you loose your last saved network when you press the Restore button (careful !).

•   Press the Store button to save your current Field settings to disk.

•   Press the Clear button to erase your Field settings to their default values. 

Notice how the "Amps" units label has now returned to its default setting of "Volts".

•   Press the Restore button to restore the previously saved settings.

Notice how the "Amps" units label has returned.  To save the settings to the file of your choosing, click the Save and Open buttons.

•   Press the Save button .  Type a file name and select a file location when the File Save dialog appears.  Remember where you put this file. 

•   Now press the Clear button to clear all settings to their default values.

•   Press the Open button and select your saved file in the File Open dialog.

Notice how the "Amps" units label now appears.  At this time, you have 2 files on your hard disk with your saved network settings.

The Reset button differs from the Clear button in that it resets the hardware in addition to clearing your fields.  It has the same affect on an instruNet network as restarting the computer.  For example, Reset will reset clock in the controller, whereas Clear will not.

BACK TO TOP OF PAGE

Working with Sensors

Any voltage input channel can attach to any of the following sensors: Voltage source, Current source, Resistance source, Strain Gage, Load Cell, Accelerometer, Potentiometer, RTD, or types J, K, T, E, R, S, B, and N Thermocouples.  Sensors can be wired in a variety of configurations including:  Differential Voltage Measurement (requires 2 voltage input channels, e.g. Ch1 Vin+ and Chi Vin-), Single-ended Voltage Measurement, Shunt Resistor, Voltage Divider, Bridge, Quarter Bridge and for strain gages: Half-Bridge Bend, Half-Bridge Axial, Full-Bridge Bend, Full-Bridge Axial I and Full-Bridge Axial II. 

•   Select the Network page by clicking on the Network tab.

•   Click on the name of the voltage input channel with the attached signal source (e.g. "Ch1 Vin+").

The Probe dialog will open with the address of the channel you clicked on displayed in the Network Address.  Additionally, the real-time value of the channel, in Engineering Units (EU) will appear at the bottom of the display, as shown in Figure 2.11.

Figure 2.11  The Snapshot Display

•   Select Hardware in the Settings popup, as shown in Figure 2.12.

Figure 2.12  Hardware Settings Area

•   Click on the Sensor popup to view the various Sensors that can directly be attached to this channel, as shown above.

This popup tells instruNet which sensor is connected to your physical hardware terminals (instruNet has no way of seeing what is out there).  For more detailed information on connecting sensors to instruNet, please refer to Connecting to Sensors.

•   Click on the Wiring popup and view the choices, as illustrated to the right.

The Vin+ - Vin- option is used for differential Voltage measurements to measure the voltage between the Vin+ and Vin- terminals.  The "common" signal on both terminals is ignored, and therefore this technique can be used to reduce noise.  The Vin+ - Gnd option specifies Singled-Ended voltage measurement, which measures the voltage between the voltage input terminal and the Ground terminal. The latter 6 options (Q Bridge, Half Bridge Bend, Half Bridge Axial, Full Bridge Bend, Full Bridge Axial I and Full Bridge Axial II are used to specify a wiring options when working with a Strain Gage sensor.  These wiring options are described in more detail in Connecting to Sensors.

•   Click on the Range popup and view the options, as illustrated to the right.  Select the largest range (e.g. +- 5V). 

This Field specifies the voltage input range.  Accuracy is increased as the range is reduced.  For example, a +-80mV range might be accurate to +-45uV, whereas a

+-5V range might only be accurate to +-1.5mV.  If you input a voltage in excess of a bound, the bound is read.  For example.  If you apply 3V  a voltage input with a +-1.25V range, then +-1.25 will be read by the computer.

•   Click in the Low Pass popup and view the options, as illustrated to the right.
The options that you see will depend on the connected hardware device. This Field is used to select an analog filter at the front end of the voltage input amplifier. 

Averaging you Signal with Integration
The Integrate field in the Hardware settings dialog, illustrated above in figure 2.12, specifies how long, in Seconds, instruNet averages an input signal before 1 number is returned to the user.  This is often used to reduce high frequency noise that has been added to a signal.  The integration feature is implemented by sampling the signal many times with the A/D converter, as fast as it can, and then averaging the A/D values with software.  The maximum allowable integration time depends on the number of digitized channels and the sample rate.  For example, 2 channels could be sampled at 1000s/sec per channel and integrated each for .5ms.

If the instruNet system reduces your sample rate to an unacceptable level, or your analog voltage data is too noisy, please see SAMPLE RATE VS. INTEGRATION VS. NOISE.

•   Select Constants in the Settings popup, as illustrated in Figure 2.13.

Figure 2.13  Constants Settings Area

These Fields are used to specify constants that are used to calculate engineering units when working with Resistance, Current, RTD, Load Cell, Accelerometer, Potentiometer, and Strain Gage sensors.  For example, Rshunt specifies the value of the shunt resistor, in ohms, when doing a Resistance measurement.  Please refer to Connecting to Sensors for details on how to use these.

•   Click OK in the Probe Dialog to return to the Network page.

•   Enable the first three voltage input channels for digitizing by clicking once on Column #5 of each channel, as illustrated in Figure 2.14.

Figure 2.14  First 3 channels of Model 100 are enabled for digitizing.

•   Select the Record page by clicking on the Record tab at the bottom of the window.

•   Click the Start button to begin recording.

The Record Page automatically creates a separate display for each recorded channel, as shown in Figure 2.15.  The actual signal that appears will depend on the connected signal sources.

•   Click the Stop button to Stop recording.

Figure 2.15  Three Channels in Record Page

Each display has a Channel Name box which appears to the right of the display, as shown to the right and in figure 2.15.  This box displays the channel name and the real-time channel value in Engineering Units. 

•   Click on the ChannelName box of the top-most display to open the Probe dialog at the Display settings area, as show in Figure 2.16.

Figure 2.16  Display Settings

•   Change the Display Max Field to 2, change the Display Min Field to -2, and click the lower-right Enter button. 

These 2 Fields are used to set the top and bottom plot values of the vertical axis in both the Record page display and the Probe dialog snapshot display.   These changes take affect when the Enter button is pressed, and can be viewed at the bottom of the Probe Dialog, as shown in Figure 2.17.  In many cases, one must edit these values, depending on the Engineering Unit range of the digitized signal.  For example, one might set 0 and 100 for a temperature that ranges from 0 to 100C.

Figure 2.17  Probe display with E.U.'s set to +/- 2V

•   Press OK to exit the Probe dialog, and then press Start to begin recording.

Notice how the vertical axis scale change effects the appearance of the recorded signal, as shown in Figure 2.18.

Figure 2.18  Record Page with top display Min/Max E.U. set to +/- 2V

BACK TO TOP OF PAGE

Working With Calibration, Different Scales, and Mapping

instruNet supports Calibration and Converting to different scales (e.g. show psi at sensor instead of Volts at screw terminals) with a 2 point mapping scheme.  All channels have a Mapping settings area that defines the relationship between "internal units" and "external units".  Internal units are the native units used by instruNet, such as Volts.  External units are what the user sees in the Record page, the Network page, and the numbers returned by iNet().  External units are linearly mapped to Internal units, and are therefore defined with 4 numbers, that define 1 line ({x1,y1}, {x2,y2}), on an Internal Units Vs. External Units 2-dimensional coordinate axis plane.

Sounds a little complicate?  Imagine a linear temperature sensor that puts out .1Volts when dipped in ice water (0°C) and 1Volts when dipped in boiling water (100°C); and you want instruNet to display °C numbers in the Record page and the Network page.  To do this, one would set the Mapping fields to:

internal1: 0.1 (Volts)    internal2: 1.0 (Volts)
external1: 0 (°C)         external2: 100 (°C)

And set the Units Label field in the General Settings area to "C".  The Units Label does not effect instruNet numerically, yet is interpreted as random text that is simply placed next numbers (i.e. it is a "label").  The Mapping fields; however, effect numbers, yet not labels.

The Mapping numbers can also be used to implement calibration.  Suppose a thermocouple (i.e. temperature sensor) is attached to instruNet and is already returning °C numbers (since that is the native units for the thermocouple), yet you find there is a 2°C offset error in your sensor, and want instruNet to "correct" for this error.  To do this, the user would set up a mapping from internal units to external units that reflected the offset error.  e.g.

internal1: 100 (°C)    internal2: 0.0 (°C)
external1: 102 (°C)    external2: 20 (°C)

Notice that Mapping can be used to correct for an offset error by adding a constant and can correct for a gain error by multiplying by a constant.

The Mapping setting area describes a line using two different methods: two points "{x1,y1}, {x2,y2}", and "y = x*scale + offset".  One can use either method.  For example, instead of setting the above 4 values, one could have set the Offset field to 2.0, to show a 2°C Offset.  When the Scale or Offset fields are changed, the x1, y1, x2, y2 fields update automatically to reflect the new line when the OK or Enter button is pressed.

Calibration Options
Please see Calibration for information on how and when to software Calibrate instruNet Hardware.

BACK TO TOP OF PAGE

Working with Digital Filters

All voltage input channels support digital lowpass, highpass, bandpass and bandstop filters.  The cut-off frequencies, minimum dB stopband attenuation (i.e. filter order), maximum dB passband attenuation, and filter type (e.g. elliptic, Chebyshev B, Chebyshev S, and Butterworth) can all be programmed separately for each channel via the Lowpass, Highpass, Bandpass and Bandstop Settings areas.  In fact, these 4 models can be run at the same time (i.e. in serial) to simultaneously do lowpass, bandpass, bandstop and highpass filtering on the same channel.  For example, one might only want to see frequencies between 20 and 1000Hz, except for the 55 to 65 band.  This would involve a highpass filter at 20Hz, a bandstop filter between 55 and 65Hz, and a lowpass filter at 1000Hz.

•   Select the Network page by clicking on the Network tab and then press the Reset button to reset the network and all Fields.

•   Click the channel name cell of the channel that is attached to your signal source (e.g. Ch1 Vin+), and then select Lowpass in the Settings popup, as shown in Figure 2.19.

Figure 2.19  Lowpass Filter settings area

The lowpass filter is illustrated in Figure 2.20.  Notice that 4 numbers are needed to describe the lowpass filter: minimum stop band attenuation (dB), maximum pass band ripple (dB), pass band cut-off frequency (Hz) and stop band cut-off frequency (Hz).  And notice how these 4 numbers corresponds to the StopB Attn, PassB Ripple, PassB F1 Hz, and StopB F1 Hz Fields in the Lowpass Filter settings area.

•   Turn the filter On by selecting Elliptic in the Filter popup (or any of the other options other than Off).

•   Enter a passband cut-off frequency value into the PassB F1 Hz field, a stopband cut-off frequency into the StopB F1 Hz field, a minimum stop band attenuation into the StopB Attn field, and a maximum pass band ripple into the PassB Ripple field.  Acceptable values would be {100, 150, 80, 1}.  Press the Enter key when done setting the values.  If the filter is impossible to design due to constraints of the specified values, an alert will appear with a message coaching the user into selecting different parameters. In fact, instruNet will not allow you to exit this dialog until the parameters are acceptable, or the filter has been turned off by selecting Off in the Filter popup.

Figure 2.20  Lowpass Filter Model

The filter order ranges from 1 to 32 in bandpass and bandstop filters, and from 1 to 16 in highpass and lowpass filters, depending on the supplied parameters.  As the filter becomes more demanding, the filter order increases, and the time to run the filter also increases.  In a typical case, it takes .1 to 2us per order per point to run the filter.  For example, on a Macintosh 840av (1993 technology) it takes 2us per order per pt or 20us per point to implement a 10th order filter.  This would limit the maximum sample rate to 50Ksamples/second (i.e. 1 / 20e-6 = 50e3).

•   View the results of your filter by observing the effect it has on the waveform in the Snapshot display.  If you have a function generator connected, watch what happens when you slowly change its frequency from 10Hz to 500Hz, for example.

Figure 2.21 shows a 35 Hz signal applied to Ch1 Vin+, before and after the implementation of a 30 Hz lowpass filter.

Figure 2.21  35 Hz Sine Wave before and after 30 Hz Lowpass Filter

Figures 2.19 through 2.21 show the filter models for the Highpass, Bandpass and Bandstop filters. 

Figure 2.22  Highpass Filter Model

Figure 2.23  Bandpass Filter Model

Figure 2.24  Bandstop Filter Model

Table 2.1 shows which fields in the Settings area must be set for each filter model.

Table 2.1  Fields required for each Filter model

•   Play with the different filter models and settings while viewing their effects in the snapshot display.  For example, to turn on a highpass filter, select Highpass Filter in the Settings popup, select Elliptic in the Filter popup, and then set the PassB F1 Hz, StopB F1 Hz, StopB Attn, and PassB Ripple fields as desires using Figure 2.19 as a guide.  Remember to press the Enter button to create the filter.

BACK TO TOP OF PAGE

Working with Voltage Output Channels

Some hardware devices, such as the Model 100, provide Voltage Output channels.  In summary, these channels output the Voltage specified in the Value Output field within the General settings area.  Voltage Output channels are named ChX Vout in the Network Page.

•   In the Network page, click on the 1st cell of the first voltage output channel.  For the Model 100, this would be the "Ch3 Vout" channel.  When the Probe dialog opens, set the Value Output field to 1, and press the Enter button.

The analog output channel is immediately updated to the new value when Enter is clicked.

•   Click OK to return to the Network page and view the ValueInput column for the chosen Voltage output channel.  It should display a value in the vicinity of 1V.

With Voltage outputs, instruNet reads back the output voltage and displays this value in the ValueOut column.  This is useful information when loading of the output signal will change its value.  An example of this is a bridge excitation circuit where it is important to know the value of the excitation voltage within a small margin (e.g. to ±.01%) yet the actual voltage only needs to be within several percent of the target voltage.

BACK TO TOP OF PAGE

Working with Digital I/O Channels

Some hardware Devices provide Digital I/O channels.  For example, the Model 100 Device offers 8 bi-directional digital I/O bits where 8 different terminals physically marked "DIO1..DIO8" can be set up independently as either a digital input or digital output.  With the Model 100 digital outputs, 0 to .8V is a logic 0, and 2V to 5V is a logic 1; however, with the Model 100 digital inputs, 0 to 1V is a logic 0, and 3.2V to 5V is a logic 1.  Also with these signals, voltages above 12V or below -12V will result in physical damage (careful !).  These 8 hardware bits are all handled by 1 instruNet channel named "Ch25 Dio", where the 8bits are read from or written to with a 1 byte word (i.e. 8 bits in a number between 0 and 255). 

To set digital output bits, such as those on the Model 100, it is necessary to do the following kinds of things:

•   Click on the cell that contains the name of a Digital I/O Channel (e.g. "Ch25 Dio") and select Hardware in the Settings popup menu.

The Direction field specifies the bit direction, where a value of 1 specifies output, and 0 specifies input.  This field packs the 8bits into one 0 to 255 number, where d0 corresponds to DIO1, d1 corresponds to DIO2, etc.  For example, 410 = 000001002 would specify DIO3 as an output, and the rest of the hardware bits are inputs.  A Direction value of 010 = 000000002specifies all hardware bits as inputs, and a value of 25510 = 111111112 specifies all bits as outputs.

The Digital Out field is used to set the state of the bits that have been marked as outputs by the Direction field.  It does this with one 0 to 255 number where each bit in the byte sets its corresponding hardware bit.  For example, if 8 bits were set up as outputs, then a Digital Out value of 1710 = 000100012 would set DIO1 and DIO5 to a logic 1, and the rest to a logic 0.

The Value EU field in the General settings area is used to read the states of the 8 bits via a 0 to 255 number where each bit in the received byte corresponds to a hardware bit.  For example, reading 310 = 000000112 would mean that hardware bits DIO1 and DIO2 are high, and the rest are low.

•   Set the Digital Out field to 110 = 000000012, set the Direction field to 310 = 000000112 and click the Enter button to update the bits.

•   Select General in the Setting popup menu and note the value displayed in the Value EU field. 

Value EU should show 25310 = 111111012.  This is because the high 6 bits have been set up as digital inputs in the Direction field, and if nothing is connected to them, they will float high to a logic 1.  DIO1 is set up as an output in the Direction field, and has been set to a 1 in the Digital Out field, and is therefore read as a 1.  DIO2 has also been set up as an output in the Direction field, yet has been set to a 0 in the Digital Out field, and is therefore read as a 0.

BACK TO TOP OF PAGE

Working with i200 Controller Digital Timer I/O Channels

The Model 200 (not 230) instruNet Controller boards have 10 digital input/output channels, each of which can be operated in the following modes:

1. Digital Input: Read logic 1 (>2V) or logic 0 (<.8V) at input pin.

2. Digital Ouput: Set connector pin to logic 1 (>2V) or logic 0 (<.8V).

3. Clock Output: Output a continuous clock, or a fixed number of pulses {1...2e9}. Set high time and period of clock. If period > 10ms, then we generate clock with a 1ms timebase that drives two 0 to 32K timers; otherwise, we use a .25us timebase. Periods must be >100us when fixing the # of pulses.

4. Pulse Counter: Read a 64bit counter that counts incoming >100us pulses since reset.

5. Period Measurement: Measure the duration of 1 to 2e9 periods by counting a .25us or 1ms timebase with a 64bit counter via the following options:

1. "Cycles" - aggregate number of periods to measure (between 1 and 255, or multiple of 10 if between 256 and 2e9). e.g. 100 cycles of 10Hz yields 10sec. Minimum pulse duration is 100us when measuring < 10 periods; and >10us otherwise.
2. "Measure" sum of entire cycle or just sum of high durations.
3. Count high "Resolution" 0.25us or lower resolution 1ms timebase
4. "Modes":
   

• Wait & Continue: Wait till measurement completes, start another measurement after read result.
• Wait & Reset: Wait till measurement completes, start another measurement when next read.
• No Wait & Continue: Read 0 if not done, start another measurement after read result.
• No Wait & Reset: Read 0 if not done, start another measurement when next read.

6. Frequency Measurement: Same as Period Measurement, except it returns the frequency of the input signal after measuring the period for "Clk Period" seconds. It checks to see if it passed the "Clk Period" second duration every "Cycles" (1...255) input pulses. For example, if you set "Cycles" to 100, and are measuring a ~10KHz signal, and set the "Clk Period" to 0.1sec, w/ a 0.25us resolution, then it will count the 4MHz timebase w/ a 64bit counter (overflows after 146,000 years). It will check to see if it passed the .1sec mark every 100 pulses (e.g. 10ms for 10KHz input). So it might stop after .11secs and see a timebase count of ~440,000 for ~1100 cycles. It will then divide these 2 numbers and return to you a VERY accurate frequency measurement (e.g. 10,000.00). Notice that traditional frequency measurement devices count a timebase for an specific duration, and error by the fraction of the input cycle that has transpired since its last trigger edge. The minimum pulse duration is 100us when measuring < 10 periods; and >10us otherwise.

7. Quadrature Measurement: Returns the 4x position of a quadrature sensor with a +/-32K counter. Connect wire A to Channel N, connect wire B to Channel N+1, and program Channel N for Quadrature, and away you go. For details, see Working with Quadrature Sensors . NOTE: High speed >1Ks/sec/ch digitizing of analog signals by the instruNet Controller ties up the dsp processor, and therefore inhibits it from doing the following during that time: pulse counter, output a specific number of clock pulses, period measurement, and frequency measurement.

Each counter/timer channel runs independently of the others, and of the other channels on the network.  For example, "Ch1 Timer" is the first channel in a controller board.  Its network address is Device 0, Module 1, Channel 1; and its physical location is two pins on a 34 pin header connector located on the controller board.  The two connector pins are labeled "Ch1 Din" and "Ch1 Dout", one for digital input and one for digital output.  With the controller digital outputs, 0 to .8V is a logic 0, and 2V to 5V is a logic 1; however, with the controller digital inputs, 0 to .8V is a logic 0, and 3.5V to 5V is a logic 1.  Also with these signals, voltages above 6V or below -6V will result in physical damage (careful !).  An instruNet Field is used to specify the function of Channel 1 as digital input, digital output, clock output or period measurement.  If digital input or period measurement are chosen, the "Ch1 Din" pin is used; otherwise, the "Ch1 Dout" pin is used.

Figure 2.25  The Timer Settings Area

Physically, all controller channels are accessed at a 34 pin header connector (.025" square pins with .1" spacing) located on the Controller board.  This connector is independent of the DB25 Connector that is used to cable to the network Devices.  One typically cables to this connector via a 34-wire ribbon cable that terminates outside the computer at a screw terminal panel.

•   Select the Network page by clicking the Network tab, and then click in Column #1 of the first controller's Ch 1 Timer channel (you might need to scroll down a little). When the Probe dialog appears, select Timer in the Settings popup, as illustrated in Figure 2.25.

The Function popup selects the channel's Function, as described below:

Digital Output  
The "ChX Dout" connector pin is set to a logic 0 (0-.8V) if the Value I/O field in the General settings area is set to a 0; otherwise, this pin is set to a logic 1 (2V-5V).

Digital Input     
The Value I/O field in the General settings area is read as 0 if the "ChX Din" connector pin is held by an external source below .8V (otherwise, it floats to 5V).  However, if this pin is above 3.5V, it is read as a 1.

Clock Output     
A square wave clock signal is driven out of the "ChX Dout" connector pin where the cycle time is specified by the Clk Period field, in units of seconds, and the high time is specified by the Clk Out Hi field, in units of seconds.

Period Measurement              
The duration of the signal applied to the "ChX Din" connector pin is measured and returned in the Value I/O field of the General settings area, in Seconds units.  If the Measure field is set to Cycle time, the time is measured between consecutive falling edges; otherwise the time is measured between a rising edge and the next falling edge. The Meas Cycles field varies from 1 to 255 and sets the number of cycles (or high times) that must occur over the measured duration.  For example, measuring 10 cycles of a 1KHz square wave would return 10ms; whereas measuring 5 high times of a 20KHz square wave would return 125us.  If the Meas Resol popup is set to .25us, the measurement is accurate to +/- .25us and the falling-edge-to-falling-edge time (or rising-edge-to-falling-edge) must range from 3us to 16ms if Meas Cycles is 1, and 3us to 4.1sec if Meas Cycles > 1. Otherwise, if the Meas Resol popup is set to 1ms, the measurement is accurate to  +/- 1ms and the falling-edge-to-falling-edge time (or rising-edge-to-falling-edge) must range from 3ms to 32 secs if Meas Cycles is 1, and 3ms to 16Ksec if Meas Cycles > 1.

Table 2.2 shows which Fields are used for each of the different functions.  instruNet ignores settings not needed for a particular function.  For example if Digital Input or Digital Output is selected in the Function popup, instruNet ignores all other Fields in the Timer area. 

Table 2.2  Fields used with different Controller Digital I/O Functions.

We will now set up one channel as a clock output and measure its duration with another channel.  This will require a 34 wire screw-terminal block cabled to the digital connector on a Model 200 instruNet Controller board.  If you do not have a screw terminal block wired to your Controller, you can still do this experiment, yet the measured period will not be correct.

•   Connect a physical wire between Pin #6 (Ch1 Dout) and Pin #7 (Ch2 Din) of the Controller Digital I/O connector.

•   Set the Function popup to Clock Out, the Clk Period field to .005, and the Clk Out Hi field to .001.

•   Select General in the Settings popup and set the User Name field to "Clock Out".

•   Click the Enter button in the bottom right of the Probe Dialog to start the clock output.

•   Select Ch2 Timer in the upper-right Channel popup to select the 2nd channel in you instruNet Controller.

•   Set the User Name field to "Clock Meas".

•   Select Timer in the Settings popup.

•   Set the Function popup to Period Meas, set the Resolution popup to .25µs, set the Measure popup to Cycle Time, and set the Meas Cycles field to 1; as shown in figure 2.25.

•   Press OK to return to the Network page. 

Notice how the names of your first two Controller channels have changed to "Clock Out" and "Clock Meas", and how Clock Meas's Value field is displaying .005 seconds of measured period.  This is the period of the clock signal being output by Ch1 Timer and being measured by Ch2 Timer.  If you remove the wire connecting the Output of Ch1 Timer and the input of Ch2 Timer, the Value field will change.

Figure 2.25  Timer Settings for Period Measurement

High speed >1Ks/sec/ch digitizing of analog signals by the instruNet Controller ties up the i2x0 DSP processor, and therefore inhibits it from doing the following during that time: pulse counter, output a specific number of clock pulses, period measurement, and frequency measurement.

For more details on the counter timer features, please click here.

BACK TO TOP OF PAGE

Working with the i2x0 Controller, Time Since Reset Channel

The instruNet Controllers offer a channel that provides the time, accurate to .25us, since the Controller was last reset.  A reset occurs when instruNet is first used after power up, the computer resets, and when the Reset button is pressed in the Network page.  This clock channel is called "Ch12 Time" and returns a number in units of seconds that is derived from a 62bit counter that counts 4MHz.

•   Select the Network page by clicking the Network tab, and scroll down until you see the Controller's Ch12 Time channel.  Notice how the Value cell slowly increments at a 1 second rate.

BACK TO TOP OF PAGE

Working with Multiple Controllers

instruNet supports multiple controllers (i.e. networks) in one computer.  In this case, the meaning of the "network number" becomes more important, since it selects a particular network in the data tree from which to operate.  To digitize simultaneously from multiple controllers, one must select channels for digitizing in the Network page (any channel combination across all controllers), and then press the Start button in the Record page.  There is one complexity however, which is that each controller has its own Trigger settings.  This is because each controller operates independently (i.e. each has its own processor that manages its own data acquisition task).  To access a Trigger dialog for a specific network, press the Trigger button in the Setup Dialog, and then select a specific network in the Network popup menu.

Setting the Trigger with multiple controllers is a little tricky since one controller cannot physically see the trigger signal attached to other controllers, and each controller has no way of sending messages to its colleagues in a short period of time.  To make the digitizing from all networks trigger off the same signal, one must attach the trigger signal to one channel from each network, and set up the Trigger dialogs for each network to trigger off that one channel in each of their respective networks.

Triggering Off A Digital Input
To trigger off the instruNet 100 Ch25 Digital Input, specify this channel as the trigger source, attach your trigger signal to Ch25 DIO8, and set the trigger threshold to 200.  When DIO8 is high (i.e. 2-5V), Ch25 is read as {128..255}; and when DIO8 is held low (i.e. 0-.8V) Ch25 is read as {0-127}.

BACK TO TOP OF PAGE

Next Step

This concludes the tutorial.  From here you might consider exploring Connecting to Sensors.

BACK TO TOP OF PAGE