Using the Instrument I/O Assistant

Summary: In this exercise, the objective is to build a VI that uses the Instrument I/O Assistant to communicate with a GPIB interface. Complete the following steps to build a VI that acquires data from the NI Instrument Simulator.

EXERCISE 1

1.A) Front Panel

1. Open a blank VI.
2. The front panel in Figure 1 will result from building the block diagram.
   

   Figure 1

1.B) Block Diagram

1. Display and build the block diagram shown in Figure 2.
   

   Figure 2

   1.  Place the Instrument I/O Assistant Express VI, located on the Functions>>Input palette, on the block diagram. Complete the following steps to configure the Express VI in the Instrument I/O Assistant dialog box.
      
      1. Select devsim from the Select an instrument pull-down menu and select VISA Code Generation from the Code generation type pull-down menu.
      2. Click the Add Step button. Click Query and Parse to write and read from the Instrument Simulator.
      3. Type *IDN? as the command, select \n as the Termination character, and click the Run this step button. If no error warning appears in the lower half of the dialog box, this step has successfully completed.
      4. To parse the data received, click the Auto parse button. Notice that Token now appears in the Outputs pane on the left side of the dialog box. This value represents the string returned from the identification query. Rename Token by typing ID String in the Token name text box.
      5. Click the Add Step button. Click Query and Parse. Type MEAS:DC? as the command and click the Run this step button.
      6. To parse the data received, click the Auto parse button. The data returned is a random numeric value. Rename Token by typing Voltage in the Token nametext box.
      7. Click the OK button to exit the I/O Assistant and return to the block diagram.
   2. Right-click the ID String output and select Create>>Indicator from the shortcut menu.
   3. Right-click the Voltage output and select Create>>Indicator from the shortcut menu.
   4. Wire the Error Out output to the Simple Error Handler VI.
2. Display the front panel and run the VI. Resize the string indicator if necessary.
3. Save the VI as Read Instrument Data.vi in the C:\Exercises\LabVIEW Basics I directory.
4. Right-click the I/O Assistant and select Open Front Panel. Click the Convert button when asked if you want to convert to a subVI.
5. View the code generated by the I/O Assistant. Where is the command *IDN? written to the Instrument Simulator? Where is the voltage being read?
6. Select File>>Exit to exit the subVI. Do not save changes.

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