Set up National Instrument Multifunction Data Acquisition devices (NI DAQ) to capture energy data

As an alternative to the Energy Probe, you can use a NI DAQ device to gather energy data from your target.

Note

Power profiling is a deprecated feature, and is being removed from Streamline in a future version.

Before you begin

  • Install NI-DAQmx software on your host machine, so caiman can communicate with the NI DAQ device. This software package includes drivers for the NI DAQ device. You must use the NI-DAQmx Base software on a Linux host machine.

  • Set the location of the appropriate caiman application using the Tool path field in the Capture Settings dialog box.

    Note

    National Instruments only distribute 32-bit versions of their libraries. Therefore only the 32-bit version of caiman works with the NI-DAQ device, even on 64-bit platforms. For example, a Windows 64-bit installation of Arm® Development Studio contains a 32-bit version of caiman.

    If the pre-built caiman executable that is distributed with Streamline is insufficient, or you want to change some options, you can Rebuild caiman from source.

Procedure

  1. Connect the Ai1 connections on the NI DAQ device to go across the shunt resistor on your target.

  2. Connect Ai0 negative to ground.

  3. Connect Ai GND to ground.

  4. Loop Ai0 positive to Ai1 negative.

    The Ai0 connectors are measured across the load, which is used to derive the voltage.

    For example, the connections for NI USB-621x are:

    Connections for NI USB-621x

  5. Repeat steps 1-3 using the other connectors on the NI DAQ device to measure more channels.

  6. In the Start view, click Capture Settings.

  7. Select the NI DAQ option from the Energy capture drop-down menu.

  8. Enter a valid system name in the Device field.

    To get the system name of your National Instruments device, you must run the NI-DAQmx Base List Devices application, which is installed as part of the NI-DAQmx software package.

  9. In the Tool path field, click Select the energy capture tool eye.

  10. Locate either the pre-built caiman in your Arm Development Studio installation directory, or the modified version that you built from source, and select it.

  11. Click Open.

    Note

    The NI DAQ device takes a while to initialize with the NI-DAQmx Base drivers, therefore the first 3-8 seconds of power data is not captured.