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MSP430F67791: need help to edit emeter calibration software for EVM430-F6779

kunal bagewadi
Prodigy 120 points

Part Number: MSP430F67791

Hi, I purchased EVM430-F6779 kit a while ago and was provided with the calibration software to calibrate the meter. I'm experimenting on the kit and need to edit the software and enhance it. Calibration GUI given in page 30 of note slaa577g. I need to discuss with TI engineer whether I have the complete source files because I am not able to build it in visual studio.

Thanks

  • 0
    TI__Mastermind 49692 points
    Hi Kunal,

    Unfortunately, the source code for the GUI is not available. It was designed to allow user's to calibrate the device and view measured power/energy values easily. The GUI sends commands back and forth with the MSP430F67791, so refer to the 'emeter-dlt645.c' file, which has a state machine implemented for structuring and sending the data back in a specific format. For your application, you can customize this file to adhere to the protocol for your specific application/interface.

    Regards,

    James

    MSP Customer Applications
  • 0 in reply to James Evans
    Prodigy 120 points
    Hi James,
    By the method you suggested, can you let me know if the following customization is possible:
    Currently, the calibration software reads the voltage and current values of the 3 phases and then the user enters the percentage error in the GUI. I want to automate this process by telling the calibration software what the desired voltage and desired current values are. In that way, the calibration software can automatically calculate the percentage error and calibrate the meter. Can this be done without editing the calibration software source files and by editing only the 'emeter-dlt645.c' file ?
    Thanks
    -Kunal
  • 0 in reply to kunal bagewadi
    TI__Mastermind 49692 points

    Let's assume you have two EVMs. For the first one, you calibrate it by following the instructions in the User's Guide. In the GUI, you can obtain the calibration factors. After performing the calibration process, you can take these factors and manually update them in the 'emeter-3ph-neutral-6779(A).h' file. These factors can be found between Lines 580 and 635. You would need to rebuild the projects and then program the second EVM. This is an alternative method for manually calibrating a device. Here, I'm assuming there are minimal differences between the components on the EVM and differences between the MSP430 devices. You could connect the GUI to see how close these factors got the second EVM to the first EVM.

    For performing the calibration automatically, I wouldn't use the GUI. Instead, I would figure out the protocol expected by the EVM and implement this on a host or PC using a terminal program like Serial Port Utility. Another option is to change the protocol/state machine in the dlt645 file to a simpler structure and/or commands in the state machine.

    Regards,

    James

    MSP Customer Applications

  • 0 in reply to James Evans
    Prodigy 120 points
    Hi James,
    Thank you for prompt responses.
    I understand I can edit calibration factors in 'emeter-3ph-neutral-6779(A).h' file. I cannot do this for my application as I need 100% (or 99.95%) accuracy. I need to calibrate every EVM using the calibration software.
    I am thinking on your advice of creating my own terminal program. Is this calibration algorithm TI's property ? May I ask you for the algorithm or how the calibration software implements it ?
    I do not know how the calibration software takes in the percentage errors and converts it to calibration factors.
    Thanks
  • 0 in reply to kunal bagewadi
    Prodigy 120 points
    Hi James,
    Please reply.
    Thanks
  • 0 in reply to kunal bagewadi
    TI__Mastermind 49692 points

    Looking at the example calibration factors in Figure 25 in the User's Guide, the error percentage should be the amount of change applied to the existing calibration factor. For example, if the voltage calibration factor is 10651 and you need to increase it by 5%, the new voltage factor should be equal to 10651 + (0.05 * 10651) = 11183.

    Regards,

    James

    MSP Customer Applications

  • 0 in reply to James Evans
    Prodigy 120 points
    Thank you James.
    I shall try modifying the calibration factors this way.

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