IVI Configuration Store

Benefits of an IVI Configuration Store

By providing a way to configure the relationship between drivers and I/O references, an IVI^® configuration store greatly enhances instrument interchangeability.

Suppose your code uses only a specified driver to communicate with one type of instrument at a fixed location. If you change the instrument model, instrument location, or driver, you would have to modify the code to accommodate that change.

An IVI configuration store offers the ability to accommodate different instrument models, drivers, or ports, without having to modify your code. This interchangeability is especially useful when you use code that cannot be easily modified.

Components of an IVI Configuration Store

The components of an IVI configuration store identify:

• Locations of the instruments to communicate with

• Software modules used to control the instruments

• Associations of software modules used with instruments at specific locations

Component	Description
Software module	A software module is instrument-specific, and contains the commands and functions necessary to communicate with the instrument. The instrument vendor commonly provides software modules, which you cannot edit from the MATLAB® Command Window.
Hardware asset	A hardware asset identifies a communication port connected the instrument. Configure this component with an IOResourceDescriptor. Usually you have one hardware asset per connection location (protocol type, bus address, and so on).
Driver session	A driver session makes the association between a software module and a hardware asset. Generally, you have a driver session for each instrument at each of its possible locations. Identical instruments connected at different locations can use the same software module, but because they have different hardware assets, they require different driver sessions. Different kinds of instruments connected to the same location (at different times) use the same hardware asset, but can have different software modules. Therefore, they require different driver sessions.
Logical name	A logical name is a configuration store component that provides access to a driver session. You can interpret a logical name as a configurable pointer to a driver session. In a typical setup, the code communicates with an instrument via a logical name. If the code must communicate with a different instrument (for example, a similar scope at a different location), update only the logical name within the IVI configuration store to point to the new driver session. You need not rewrite any code because it uses the same logical name.

Configuring an IVI Configuration Store

Using the GUI

You can use the Test & Measurement Tool to examine or configure your IVI configuration store. Open the tool by typing:

tmtool

Expand the Instrument Drivers node and click IVI.

You see a tab for each type of IVI configuration store element. This figure shows the available driver sessions in the current IVI configuration store. For the selected driver session, you can use any available software module or hardware asset. This figure shows the configuration for the driver session TekScope.DriverSession, which uses the software module TekScope.Software and the hardware asset TekScope.Hardware.

Using the Command Line

Alternatively, you can use command-line functions to examine and configure your IVI configuration store. To see what IVI configuration store elements are available, use instrhwinfo to identify the existing logical names.

instrhwinfo('ivi')
ans = 
              LogicalNames: {'MainScope', 'FuncGen'}
                ProgramIDs: {'TekScope.TekScope','Agilent33250'}
                   Modules: {'ag3325b', 'hpe363xa'}
ConfigurationServerVersion: '1.6.0.10124'
  MasterConfigurationStore: 'C:\Program Files\IVI\Data\
                             IviConfigurationStore.xml'
               IVIRootPath: 'C:\Program Files\IVI\'

Use instrhwinfo with a logical name as an argument to see the details of the configuration.

instrhwinfo('ivi','MainScope')
ans = 
            DriverSession: 'TekScope.DriverSession'
            HardwareAsset: 'TekScope.Hardware'
           SoftwareModule: 'TekScope.Software'
     IOResourceDescriptor: 'GPIB0::13::INSTR'
SupportedInstrumentModels: 'TekScope 5000, 6000 and 7000 series'
        ModuleDescription: 'TekScope software module desc'
           ModuleLocation: ''

You can use the command line to change the configuration store. Here is an example of changing it programmatically.

% Construct a configStore.
configStore = iviconfigurationstore; 

% Set up the hardware asset with name myScopeHWAsset, and resource descriptor 
%    TCPIP0::a-m6104a-004598::INSTR.
add(configStore, 'HardwareAsset', 'myScopeHWAsset', 'TCPIP0::a-m6104a-004598::INSTR'); 

% Add a driver session with name myScopeSession, and use the asset created in the step above. 
%    Ag546XX is the Agilent driver. 
add(configStore, 'DriverSession', 'myScopeSession', 'Ag546XX', 'myScopeHWAsset');

% Add a logical name to the configStore, with name myScope and driver session 
%    named myScopeSession. 
add(configStore, 'LogicalName', 'myScope', 'myScopeSession'); 

% Save the changes to the IVI configuration store data file.
commit(configStore); 

% You can verify that the steps you just performed worked.
logicalNameInfo = instrhwinfo('ivi', 'myscope') 

Basic IVI Configuration Store

Following is an example of configuration used by data_analyzer.m.

Create and configure elements in the IVI configuration store using the IVI configuration store object methods add, commit, remove, and update. For further details, see the reference pages for these methods.

IVI Configuration Store with Several Interchangeable Elements

The following figure shows an example of an IVI configuration store with several interchangeable components. Code 1 requires access to the oscilloscopes at two different locations (hardware asset X and hardware asset Y). The scopes are similar, so they use the same software module S. Here, the scopes are at different locations (or the same scope connected to two different locations at different times). Therefore, each configuration requires its own driver session, in this example, driver session A and driver session B.

Write Code 1 to access logical name 1. You configure the name in the IVI configuration store to access driver session A or driver session B (but not both at the same time). Because you select the driver session in the IVI configuration store, you need not alter the code to change access from one scope to the other.