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Controlling SMU Power Allocation

    Last Modified: May 12, 2020

    The Power Allocation properties allow you to control when errors are generated in situations that could cause the SMU to source more power than is possible on a single channel or on the entire module.

    1. Add the NI-DCPower Power Allocation Mode property to your program and choose the mode appropriate for your application.
      Mode Description
      Disabled Disable driver checks to ensure that the individual channel configurations cannot result in exceeding the maximum power available to the module. Hardware monitoring of maxiumum module power is still active, and if this limit is exceeded, a board-level error will be triggered which shuts down the module to prevent damage and requires a reset to clear.
      Automatic The driver calculates required channel power from the configured voltage level/current limit or current level/voltage limit and attempts to allocate that power from the available total module power at commit. If there is insufficient power available to be allocated, NI-DCPower returns an error which requires the configuration to be changed to be within the available unallocated power or for power to be deallocated from another channel to clear. Other channels are not impacted by these errors.
      Manual The driver attempts to allocate channel power from the available total module power, but the user explicitly defines the required channel power level using the Requested Power Allocation property.

      When the NI-DCPower Power Allocation Mode property is set to Automatic or Manual, you can read back the power the SMU is sourcing on any active channels with the NI-DCPower Actual Power Allocation property.

    2. If Manual mode is selected, set Requested Power Allocation to the desired sourcing value for that channel. If Power Allocation Mode is set to Disabled or Automatic, no action is necessary.
    3. If using Manual mode, resolve possible errors. An error can occur for the following reasons:
      • Requested Power Allocation is more than the channel power limit.
      • Requested Power Allocation is more than the available total module power.
      • Maximum power the channel could source with its level/limit configuration is more than the Requested Power Allocation.

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