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TMDSHVMTRINSPIN(296-25715-ND) adding external DAQ

James Oh2
Prodigy 110 points
Other Parts Discussed in Thread: TMDSHVMTRINSPIN, MOTORWARE

Hi, I'm currently using TMDSHVMTRINSPIN for my motor control experiment and am having some difficulty due to control cards(F28335) capability limitations of data acquisition rate of only 60kHz(using only one channel). 

I would like to add an external DAQ to acquire phase current, terminal voltage and DC link voltage data which can sample data at a rate faster(over 1MHz) than the DAQ system embedded in the TMDSHVMTRINSPIN. 

I saw there are ports(I'm not sure if I can call them ports but anyway) on the board as in the picture where I can connect wires to.

I see in the circuit diagram that I would be able to measure Vfb-U, Vfb-V, Vfb-W, Ifb-U, Ifb-V, Ifb-W, Vfb-BUS, and even PWM signals. 

Are these ports meant for this purpose? or is connecting an external DAQ not recommended during operation?

Thank you in advance!

  • 0
    TI__Guru** 115440 points

    It's a test point for connecting the probe of the oscilloscope. Please note that the high voltage kit is hot ground design, so we don't recommend to connect these ports to an non-isolation instruments directly. You might connect it to an external DAQ during operation if the DAQ is isolation connection.

  • 0 in reply to Yanming Luo
    Prodigy 110 points

    thank you for your answer 

    But, I'm not sure about what you mean by hot ground design. Do you mean floating ground?

    Can you also tell me the reason why it's not recommended to connect a non-isolation instrument directly? I'm assuming it's because of the inaccurate reading due to fluctuation of potential in the ground?

    If this is the reason, then I'm curious how the TMDSHVMTRINSPIN accurately samples the current data for motor control since the ADC embedded in the system would also be exposed to ground fluctuation and inaccurate reading of parameters. 

    So if I were to connect a external DAQ, I would need a DAQ with ground to channel isolation right?

    Or can I just connect the TMDSHVMTRINSPIN ground to the actual ground and use non-isolated DAQ?

  • +1 in reply to James Oh2
    TI__Guru** 115440 points

    Correct. The AC rectifier generates the DC voltage the ground of which is floating from the protective earth ground. Hence appropriate caution must be taken while connecting scopes and other test equipment to the board. Recommend isolation transformers must be used when connecting grounded equipment to the EVM.

    You might take a look at the following guides.

    readmefirst_instaspin_motor_kits.pdf

    C:\ti\motorware\motorware_1_01_00_18\docs\boards\kits\docs

     

    qsg_hw_hvmtr_r1p1.pdf

    C:\ti\motorware\motorware_1_01_00_18\docs\boards\drive\hvkit_rev1p1\docs

    James Oh2 said:
    So if I were to connect a external DAQ, I would need a DAQ with ground to channel isolation right?

    Yes.

    James Oh2 said:
    Or can I just connect the TMDSHVMTRINSPIN ground to the actual ground and use non-isolated DAQ?

    No.