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Sharing an IVI Driver Among Multiple GPIB Devices

Primary Software: Instrument Drivers/IVI>>IVI Compliance Package
Primary Software Version: 2.0.1
Primary Software Fixed Version: N/A
Secondary Software: N/A
Hardware: GPIB

Problem:
I have two IVI devices that will use the same driver. However, when I configure the Driver Session, I must specify the address of the instrument (Resource Descriptor). I would like to use both instruments on the same GPIB network. Even when I create separate Logical Names for the instruments, I cannot specify a different Resource Descriptor. How can I specify a different address for my second instrument?

Solution:
You must create a separate Driver Session to refer to each individual device. Each Logical Name should refer to a different Driver Session, and the respective Driver Sessions are then configured independently to specify the Resource Descriptor. Steps for this process are detailed below. Please refer to the bottom of this KnowledgeBase for steps written for older versions of Measurement & Automation Explorer (MAX).
  1. Download and install the IVI driver. This driver should show up under the Driver Sessions tab in the IVI Drivers section of MAX. For example, an IVI driver called InstrDriver will now show up as described.

  2. Right click the Driver Sessions tab and click Create New. Use a descriptive name such as InstrDriver2.

  3. On the newly created driver (InstrDriver2), select the Software Tab at the bottom of the main window.

  4. Select the correct Software Module corresponding to your instrument.

  5. Create two Logical Names for the two identical devices by right-clicking the Logical Names tab and clicking Create New. For example, we will use Instrument1 and Instrument2.

  6. For each Logical Name, specify a Driver Session corresponding to your device, but never using the same Driver Session. For example, we would assign InstrDriver to Instrument1 and InstrDriver2 to Instrument2. Each Driver Session actually uses the same driver, but they are now different sessions.

  7. Create a new Hardware Asset for each Driver Session by selecting the Driver Session, then selecting the Hardware Tab at the bottom of the main window. For this example we will create Hardware1 from the InstrDriver session and Hardware2 from the InstrDriver2 session.

  8. You can now specify a unique Resource Descriptor for each hardware device by selecting the Driver Session from the Driver Session Tab, then selecting the Hardware Tab at the bottom of the main window.

In summary, it is necessary to create a unique Driver Session for each instrument on the GPIB network. Separate Driver Sessions may use the same software module (driver). Two Driver Sessions pointing to the same driver can then be configured to have different physical addresses. Thus, two identical instruments (or two sharing the same driver) can exist on the same GPIB network.

Instructions for older versions of MAX:

  1. Create a new IVI Instrument Device for each instrument connected to the computer by right-clicking Devices and selecting Insert from the shortcut menu. Refer to the NI Developer Zone document linked below for more information about creating devices.

  2. Create a new virtual instrument for each device you created in step 1 by right-clicking Virtual Instruments and selecting Insert from the shortcut menu.

  3. Enter a unique name and brief description for the virtual instrument.

  4. Click the Next button to display the New Virtual Instrument Specific Driver dialog box.

  5. In the New Virtual Instrument Specific Driver dialog box, select Use an Existing Specific Driver and select the appropriate IVI instrument driver.

  6. In the New Virtual Instrument Device dialog box, select Use an Existing Device and select one of the devices you created in step 1.

  7. In the fourth dialog box, the wizard shows a summary of the virtual instrument to be created. Click the Finish button when you finish creating the virtual instrument. Repeat these steps for each additional instrument.

  8. Create a new logical name for each instrument by right-clicking Logical Names and selecting Insert from the shortcut menu.

  9. Enter a logical name and brief description.

  10. In the New Logical Name Virtual Instrument dialog box, select one of the existing virtual instruments that you created in steps 2 through 8.

  11. Click the Next button.

  12. In the New Logical Name Summary dialog box, click the Finish button.

  13. Repeat steps 8 through 13 for each new logical name, selecting a unique virtual instrument for each logical name.
You can tie each virtual instrument to only one physical GPIB address at a time. When the same virtual instrument is used for two logical names, changing the device associated with one logical name changes the device associated with the second logical name.

Related Links:
Instrument Drivers and NI-VISA Support 
Developer Zone Tutorial: Using Measurement & Automation Explorer 3.0 to Configure Your IVI System

Attachments:


FinalConfig.JPG - FinalConfig.JPG

Report Date: 01/10/2002
Last Updated: 05/01/2008
Document ID: 2H9DOBYP

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