A sequence is composed of steps that specify a series of outputs for an NI-DCPower channel. In a simple sequence, you can specify either a series of voltage outputs or a series of current outputs. Advanced sequencing allows you to configure multiple properties per sequence step.

For more information on using and customizing advanced sequences, refer to Advanced Sequencing.

During a sequence, the channel steps through a predetermined set of NI-DCPower configurations without any interaction with the host system and NI-DCPower. Because the host system is not involved in executing the NI-DCPower sequence changes, the changes from one step in the sequence to the next are deterministic.

Support For Sequence Mode

  • The following devices do not support this feature: PXI-4110, PXI-4130
  • Using NI-DCPower Set Sequence and Advanced Sequence functions for the same channel in the same session is not supported.

Typical Sequence Operation

The following steps illustrate the typical operation of the source unit when you initiate in Sequence source mode.

  1. (Optional: Advanced sequencing only) If the channel was previously in the Uncommitted state and you created a Commit step, the driver applies the Commit step to the channel.
    1. The source unit applies the voltage or current specified by the Commit step.
    2. The source unit waits for the source delay specified by the Commit step.
    Note The Commit step in an advanced sequence does not generate a Source Complete event.
  2. (Optional) The source unit waits for a Start Trigger.
  3. The channel steps through the sequence.
    1. (Optional) If this is not the first step in the sequence, the source unit waits for a Source trigger.
    2. The source unit applies the voltage or current in the next sequence step.
    3. After waiting the time specified by the next source delay in the sequence, the source unit generates a Source Complete event.
    4. (Optional) The measure unit takes a measurement and stores it in a buffer on the instrument.
      Note The presence of this step is dependent on the settings of NI-DCPower Measure When. If the Measure When property is set to Automatically After Source Complete, the measure unit takes a measurement after each source step. Otherwise, the measure unit operates independently of the source unit.
    5. The source unit repeats 3a through 3d for each step in the sequence.
  4. The sequence iteration is complete, and the source unit generates the Sequence Iteration Complete event.
  5. (Optional) The source unit loops back and repeats the same sequence. When it loops back, the source unit waits for a Sequence Advance trigger (if it is not disabled) and then runs through the sequence again without waiting for the Start trigger.
  6. If NI-DCPower Sequence Loop Count Is Finite is set to True, once the sequence runs the number of times specified by NI-DCPower Sequence Loop Count property, the operation is complete, and NI-DCPower generates the Sequence Engine Done event, as shown in the following figures. If NI-DCPower Sequence Loop Count Is Finite is set to False, the NI-DCPower Sequence Loop Count property is ignored, and the sequence returns to step 3a until it is aborted by calling the NI-DCPower Abort With Channels or by closing the session.

The following figure illustrates a sequence under the following conditions:



  • NI-DCPower Measure When is set to Automatically After Source Complete.
  • The source unit is not pulsing.

The following figure illustrates a sequence under the following conditions:



  • NI-DCPower Measure When is not set to Automatically After Source Complete.
  • The source unit is not pulsing.