ECE310 Login and use of Biobench data acquisition system, John G. Webster12/5/98

Login to the network and start Biobench

Computers in room 3439 biomedical engineering lab are similar to the computers in CAE NT labs. You can get access to your CAE NT account and run most of the applications from CAE servers. In the lab, you will generate files for data collection. It is strongly suggested that you save all the files on your CAE account (f:). Otherwise you will not be able to get access to your files when you write your report after the lab.

The procedures to login to the computers are similar to CAE labs.

1. Press Ctrl+Alt+Del , a login window will pop up

2. Login to network. Click on Login, input your username, context and password of your CAE account.

3. Login to local machine. Click on Windows NT, input local username as student. (Windows NT Login only, should be unchecked).

4. Click on OK, a Windows NT Workstation window appears to ask password for local login. Do not type anything and just click on OK.

5. If some windows appear, just click on OK and never restart the computer.

6. BioBench is software provided by National Instruments for data acquisition and analysis.

7. Double Click on BioBench on the desktop and wait patiently.

8. In User login, choose a user name or type your own. Click on OK.

Connect the inputs

1. Connect inputs to black interface box. Connections to the inputs of the interface box are made using single conductor wires (no connectors). The eight input channels are labeled ACH0 through ACH7, and the ground connections are labeled AISENSE/AIGND. To connect a single wire, lift the right side of the corresponding white lever to open the clamp, insert the wire into the left side, and return the lever to its original position to close the clamp onto the wire.

Acquire data

1.To begin acquiring data, be sure that the acquisition mode (labeled on the top line) is active. BIOBENCH has two modes, acquisition mode and analysis mode. To toggle between the two modes, click on the button labeled acquisition or analysis at the lower right of the panel.

2.In the acquisition mode, set up the appropriate channels for viewing. For example, choose View 1 graph acquisition. The default panel for BIOBENCH shows two channel windows. The channel number to be shown in each display window may be selected by clicking on the arrow at the upper left of each display window. If you wish to have more than two channels displayed at once, choose another selection from the VIEW at the top of the panel.

3.In the acquisition mode, set up for logging data. In order to have the data written to a file, the LOGGING section at the right side of the panel must have the LOG DATA box checked. If this box is not checked, data will be shown when in acquisition mode, but it will not be saved.

4.Set up the data logging file size and the number of active channels. The length of time that data will be saved is determined by the file size, the sampling rate, and the number of channels running in an acquisition. In the acquisition mode, to set the file size, go to FILE -> LOGGING. Type in the desired file size. LOGGING will save data while sampling. To set the number of active channels, go to CONFIGURE -> SETTINGS. A single acquired channel at 500 samples/s and a file size of 10 MB runs for about 9.7 s.

5.You can save settings. Choose Configure Setting Timing. Make start time and stop timeall On command. Set Sampling rate 500 samples/s. Choose the channels you are going to use in the lab. To save space for data, it is suggested you just choose one channel you use in the lab. Click OK. The system is set up and you can save the setting.

6.Start acquiring data. Press the green GO button in the upper right part of the panel. STOP will stop acquisition.

7.Set vertical scale. The vertical scale may be set manually (by clicking on the vertical scale and entering the limits in the box) or by pressing the auto-scale button (marked with an up-down arrow and a 'Y', located above each channel window). Changing the vertical scale setting during acquisition does not change the saved data, but only affects the current display of data.

8.Try the Filter to achieve power line interference cancellation.

Analysis

1.Switch to analysis mode, and view the desired portion of the recorded signal. The vertical scale may be changed by:

a. using the auto-scale button

b. changing the vertical scale manually (double-click on the vertical scale and enter the limits)

c. click and drag the white sliding vertical bar to change the vertical position of the viewed area, and click and drag the black ends of the sliding vertical bar to change the size of the vertical viewed area.

2.Scroll through the horizontal trace to find points of interest. Just as with the vertical scale, the horizontal view may be changed by entering the limits manually (after double-clicking on the horizontal scale) or by clicking and dragging the white and black parts of the horizontal sliding bar.

3.The horizontal view may also be changed by using the buttons at the bottom of the panel.

4.To view the entire trace, click the 4th button from the left (with blue arrows pointing out on each end).

5.To zoom in on one part of the trace, click on the trace to place a cursor on the point of interest, and click on the leftmost button.

6.To scroll to the left and right through the trace, click the single arrow buttons.

To view the entire trace and place the cursors at the ends of the trace, click the rightmost button.

7.Make measurements using the cursors. To measure times, and voltage values using two cursors, click on the trace to place the first cursor and drag to the left or right to place the second cursor. X and Y values are shown above and below the channel windows.

Exporting and printing

1.Export data for viewing in a spreadsheet and for printing. After a region of interest has been selected using the cursors, choose FILE -> EXPORT TO SPREADSHEET. After the text file name and path have been chosen (save the file either to a floppy or to your network disk space), click export. The data may be viewed and graphed from EXCEL or other graphing/spreadsheet software.

2.To get a printout of data, choose File print window

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