Measuring DUT

Power source and measure a Device Under Test (DUT)

Set up Otii hardware, either the Otii Arc Pro or Otii Ace Pro, to work as a power source box providing constant voltage to the DUT, ranging from 0.5V-5V / 0V-25V, and enable it to measure output current and voltage.

Products required

Hardware

Otii hardware setup

  1. Connect Otii hardware to your computer via USB. If needed, add a DC power supply via the DC plug.

  2. Connect Otii hardware’s banana connector positive lead to DUT positive (+) battery connector/power connector.

  3. Connect Otii hardware’s banana connector negative lead to DUT negative (-) battery connector/power connector (GND).

In case of connecting the DUT using the battery connector, remove the battery prior to connecting it to the Otii hardware.

Otii software setup

  1. Open the Otii 3 Desktop App, then select "Create a new Otii Project."

  2. In the left sidebar, find the CONTROL section. Within this section, add the Otii hardware identified by your computer. Just click the add button on the right side of the hardware identified.

  3. Considering the DUT's power ranges, set the required voltage for the added Otii hardware in the voltage box located on the left side of the power supply button.

  4. Under "General Settings," make sure that the "Power Box" option is selected, and set an OC (overcurrent) protection for the DUT.

  5. Under "Channels", select "Main current" to measure DUT's output current and "Main voltage" to measure DUT's output voltage. The "Main power" channel is assigned by default when the main current is selected to measure DUT's energy consumption.

  6. [Optional] The previously selected channels will be listed under the MEASUREMENTS section. In this section, the sampling rate, up to 50 ksps, can be set. (Only possible with the Otii Ace Pro)

  7. Click the record button in the upper left corner of the toolbar to start recording DUT measurements. Since your DUT is not powered on yet, only noise measurements will be observed at first.

  8. Turn on the DUT by clicking the power button next to the desired voltage assigned. Once turned on, the DTU measurements are being recorded.

  9. Now, it's time to validate, analyze, and optimize your embedded system or IoT devices.

Keep in mind

🔋 Use wires with the lowest possible resistance and keep them as short as possible to minimize voltage drop, especially when the DUT consumes high current. The resistance in wires will be added to the total series resistance within the system, causing an unwanted voltage drop and an error in power and energy consumption measurements.

🔋 If the DUT consumes high current during power-up, causing high voltage drops in the attached wires, which directly affects the power-up cycle of the DUT since the voltage is too low. In case of experiencing this, connect one or several capacitors from Bat+ to Bat- on the DUT side to stabilize the voltage to start up the DUT properly. Note that the Otii Arc and Otii Ace have very low output capacitance for being a power source for the DUT but also a programmable load.

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