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INA234: I2C Status Query?

johny radio
Expert 1280 points

Part Number: INA234
Other Parts Discussed in Thread: INA238

Is it possible for the I2C master to query this device for UV, OV, and OC status?

  • 0
    TI__Mastermind 36740 points

    Hi,

    The INA234 will monitor one over/under condition at any given time, not all at the same time. There is only one limit register to use for this purpose. Conversion status can be monitored (queried through I2C) in addition to one over/under condition monitoring.

    If you need to monitor multiple over/under conditions, INA238 is a good option.

    Regards

    Guang

  • 0 in reply to Guang Zhou
    Expert 1280 points

    Are you sure? I understand that the alert pin can only register a single condition. But don't all the sensors operate all the time, accessible through I2C?

  • 0 in reply to johny radio
    TI__Mastermind 36740 points

    Hi Johny,

    I'm fairly sure, however maybe there is something I overlooked. Which part of the datasheet mentioned that all over/under conditions are monitored, and corresponding statuses are accessible through I2C?

    Regards

    Guang

  • 0 in reply to Guang Zhou
    Expert 1280 points

    Address - Register Name

    1h Shunt Voltage Register

    2h Bus Voltage Register

    3h Power Register

    4h Current Register

  • 0 in reply to johny radio
    TI__Mastermind 36740 points

    Hi Johny,

    These are the value registers. Yes, these are available all the time.

    However, not all over/under statuses can be monitored.

    Regards

    Guang

  • 0 in reply to Guang Zhou
    Expert 1280 points

    When you say "monitored", you're talking about the Alert pin, correct?

  • 0 in reply to johny radio
    TI__Mastermind 36740 points

    Hi Johny,

    The ALERT pin obviously can only be associated with one condition, be it current/voltage, over or under limits.

    What I meant is the status bits. In INA238, there are multiple limit registers a user can set. Corresponding status bits are available to reflect if each of these limits are exceeded. This functionality is not available on INA234.

    this was in response to your initial post “query this device for UV, OV, and OC status”.

    Regards

    Guang

  • 0 in reply to Guang Zhou
    Expert 1280 points

    Hi Guang, 

    Thanks for that info about the INA 238. But, I'm not speaking of limits. Just obtaining the last sensor value, or the averaged sensor valve (with I2C).

  • +1 in reply to johny radio
    TI__Mastermind 36740 points

    Hi Johny,

    In that case, you’re good to go with INA234. Current, voltage and power register values are all available through I2C. I’m glad it is merely a terminology misunderstanding.

    Guang

  • 0 in reply to Guang Zhou
    Expert 1280 points

    Thanks, Guang. I see it's average:

    "Following every measured sample, the newly-calculated values for current and power are appended to this accumulation register until all of the samples have been measured and averaged. After all of the samples have been measured and the corresponding current and power calculations have been made, the accumulated average for each of these parameters is then loaded to the corresponding output registers where the values can then be read."

  • 0 in reply to johny radio
    TI__Mastermind 36740 points

    Hi Johny,

    Yes, you’re correct. If you choose the number of averaging to be greater than one, then INA234 will accumulate the single measurements until the number of averaging is reached, calculate the average and store in the registers, from which the I2C controller can read.

    Before the new results are stored, the previous results are available in the registers to read.

    Guang