Communicating with Instruments Using IVI
LabVIEW SignalExpress provides a set of IVI steps that communicate with instruments in the following IVI Classes:
- Digital Multimeter
- Oscilloscope
- DC Power Supply
- Arbitrary Waveform/Function Generator
To communicate with an instrument, you need to install the instrument-specific IVI driver and create a session name for the instrument.
Downloading and Installing the Instrument-Specific IVI Driver
Complete the following steps to download an IVI-specific driver for an instrument.
- Launch the Instrument Driver Network.
- Use the Instrument Type list on the left side of the page to find a driver for the instrument, or click the Browse Drivers link and use the Search within results field to search for the instrument you are using.
- When you find a driver you want to download, click the Model name to open the description of the driver.
- Confirm that IVI appears in the Driver Type description.
- Download and install the driver.
Creating an IVI Session Name
Each LabVIEW SignalExpress IVI step contains an IVI session name control that allows you to select the session name that you want to associate with the step. The session name identifies the driver and the instrument that you want to use with the step. From the IVI session name control, you can select a previously created session name or create a new local session name from the step.
Complete the following steps to create an IVI logical name from the step.
- Select Create New from the IVI session name.
- Enter a name and select the Resource descriptor associated with the instrument that you want to control, or enter the descriptor if it does not appear in the Resource descriptor control.
- Select the appropriate Instrument Driver and click the OK button.
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Note You can simulate your hardware by placing a checkmark in the Enable simulation data checkbox. |
Deployment
The IVI steps in LabVIEW SignalExpress communicate to an instrument through an IVI Session. The IVI Session is stored in the IVI Configuration Store, not in your LabVIEW SignalExpress project. Therefore, the IVI Session is not transferable between computers.
Deploying a LabVIEW SignalExpress Project
To bring your LabVIEW SignalExpress project to a computer that has LabVIEW SignalExpress installed, you can either reconfigure the IVI steps to use existing IVI Sessions, or if no appropriate IVI Sessions exist, create new IVI Sessions from within LabVIEW SignalExpress.
- Select Create New from the IVI session name.
- Enter a name and select the Resource descriptor associated with the instrument that you want to control, or enter the descriptor if it does not appear in the Resource descriptor control.
- Select the appropriate Instrument Driver and click the OK button.
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Note You can simulate your hardware by placing a checkmark in the Enable simulation data checkbox. |
Deploying LabVIEW Code Converted from a LabVIEW SignalExpress Project
Converted code from a LabVIEW SignalExpress project uses the same IVI Session that was configured in LabVIEW SignalExpress. If you deploy your generated code to a new machine, you must recreate the IVI Session on that machine. If LabVIEW SignalExpress is installed on the machine, refer to Distributing LabVIEW Block Diagrams for Execution. If LabVIEW SignalExpress is not installed, you can create the IVI Session using National Instruments Measurement & Automation Explorer (MAX).
- Launch MAX.
- Expand the IVI Drivers.
- Follow the instructions in the MAX category help.
You also can refer to the NI Developer Zone for more information about using MAX to configure an IVI system.
Resource Descriptor
A resource descriptor is a string, such as a VISA resource descriptor, that specifies the interface and the address of the hardware to associate with the step. The following lists examples of valid resource descriptors.
- GPIB::22::INSTR
- GPIB1::22::5::INSTR
- VXI::64::INSTR
- ASRL2::INSTR
- GPIB::22::INSTR
- DAQ::1::INSTR
- PXI1Slot2
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Note The resource descriptor is not necessary if you place a checkmark in the Enable simulation data checkbox. |
Instrument Driver
The driver list contains the list of all driver sessions to which the step can refer. By selecting a driver from the list, you are associating the session name with a particular set of properties the driver can use.
Enable simulation data
If you place a checkmark in the Enable simulation data checkbox, the specific driver functions simulate instrument I/O. If you remove the checkmark, the specific driver functions do not return random simulated values for output parameters that represent instrument data.