How do I create and use a MATLAB Instrument Driver (.mdd) file for use with my Programmable AC Load Bank NHR 4600?

I am using the Instrument Control Toolbox in MATLAB to communicate with and control NHR 4600. I have installed the appropriate there own IVI drivers for this instruments. It own application working fine, but I need to work with this device in SIMULINK environment. And this AC load bank connecting to PC trough COM! by RS 232. I am trying to create a MATLAB Instrument Driver (.mdd) file in order to control the instrument through an interface object.

When using the MAKEMID command to do this, I receive the following error:

>> makemid('NHRACLoad')

Error using makemid (line 152)
The specified driver could not be loaded.

152:     error(message('instrument:makemid:conversionErrorLoad'));

[Walter Roberson]

Is it possible that you have a class of 32 bit vs 64 bit for the drivers?

[Oleksiy Ekzarkho]

no, both working 32 bits

Answer 1

[Sai Kulkarni]

I understand that you are trying to create a MATLAB Instrument Driver for the NHR 4600 device using the 'makemid' command and receiving the

Since IVI-COM is only supported with 32-bit versions of MATLAB, I am assuming that you are using a 32-bit installation of MATLAB R2015b or earlier. All documentation links in this answer refer to MATLAB R2015a, but you can refer to the appropriate page for the MATLAB release that you are working with.

Try the following troubleshooting steps for this issue:

Basic Troubleshooting

• Are you able to view the device information using the command "instrhwinfo('ivi')"? If not, follow the directions listed on this documentation page: Getting Started with IVI Drivers
• Make sure that 'NHRACLoad' is exactly same as either the driver name or the device's logical name as it appears in the output of "instrhwinfo('ivi')".

Failure to Locate Driver File

In certain MATLAB versions, his error can occur if the IVI-C driver is installed into a folder name that does not match the driver prefix specified in the IVI Configuration Store.

To work around this issue you can change the folder name in which the driver FP-file is present to match the prefix for the driver. The following steps use Agilent 34980A as an example, but you can follow similar steps for your device as well.

• Determine the location of the IVI root directory. This can be done by examining the IVIRootPath filed returned by the command

>> iviinfo = instrhwinfo('ivi');
>> iviinfo.IVIRootPath
ans =
D:\Applications\IVI\

• Go to the IVI root directory and then into the "Drivers" sub folder.

>> cd(iviinfo.IVIRootPath)
>> cd Drivers\

• Look for your drivers directory in this folder. For example the "AqD1" driver is located in a folder called "IviAqD1"

   >> dir 

.                 AgSAn             AgilentInfiniium  ividcpwr          ivirfsiggen
..                Agilent34401      AgilentSa         ividmm            iviscope
AGN6030A          Agilent34980A     IviAqD1           ivifgen           ivispecan
AgRFPowerMeter    Agilent546XX      TekScope          ivipwrmeter       iviswtch

• Look in the directory for you driver and see the name of the FP and SUB files.

>> cd Agilent34980A     
>> dir *.fp

ag34980a.fp

• The name of the directory should match the name of the FP file. In this case, the directory name should be changed to ag34980a.fp. This also must be the name of the DLL-file in the "bin" folder of the IVI root directory. The DLL-file may have an optional "_32" appended to the end of the file.

>> cd ..
>> movefile Agilent34980A ag34980a

• You can now create the MDD-file with the MAKEMID command and use it with ICDEVICE

>> makemid('ag34980a','ag34980a.mdd')
>> instr = icdevice('ag34980a.mdd','GPIB0::1::INSTR');

• Other applications may expect the old directory name. Once the MDD-file has been generated, you can quit MATLAB and rename the directory back to its original name.

Additional Resources

• Troubleshooting IVI, VISA, and the Quick-Control Interfaces
• MathWorks Technical Support

[Oleksiy Ekzarkho]

Hi Sai. Thank you for detailed explanation. I already make .mdd file by following instruction from Getting Started with IVI drivers Getting Started with IVI drivers and Troubleshooting IVI, Visa and Quick control interfaces. At Getting Started with IVI drivers the section Verifying IVI Shared Components says:

instrhwinfo ('ivi')

ans =

. . . ConfigurationServerVersion: '1.6.0.10124'

MasterConfigurationStore: 'C:\Program Files\IVI\Data\IviConfigurationStore.xml'
             IVIRootPath: 'C:\Program Files\IVI\'

As I understand we have to make .mdd file from .xml? Also I create

So, the question is: how to connect it now? After command connect the system trying to activated but straightaway closing itself... I try it from command window and from the Test & Measurement tool as well... the result the same. The status of the system is open. when I try the .fp file it gave the message: status - close. I couldn't understand what I am doing wrong?

[Pooja Mehta]

I tried the the steps to resolve the error " Error using makemid (line 129) The specified driver could not be loaded."

Please give you input to resole this issue

if (isempty(model))
  error(message('instrument:makemid:conversionErrorLoad'));
end

[Walter Roberson]

Pooja Mehta, could you confirm that you are using R2015b or earlier with a 32 bit version of MATLAB ?

[Vinod]

Pooja: Can you make sure you have one of these VISA support packages installed

Once the support package is installed, please type in the results of executing the following at your MATLAB prompt

>> computer('arch')

Also,

>> instrhwinfo ivi