Portable Bench Testing Instrument with LattePanda 3 Delta

As an electronics hobbyist, I always want to have my own testing lab. In my professional career, I have worked with many Automated Testing Equipment and instruments. So, I came up with the idea of building my own testing setup for my personal projects and works.

In this tutorial, I'm going to show you my progress in making my own portable and powerful basic bench equipment.

Instruments Selection:

First, we have to finalize what are the instruments we are going to use in our lab setup. For a basic measurement system, we need a multimeter to measure the current and voltage.

But the normal multimeter is not going to work when you are building automated bench testing equipment. Our instruments need to be controlled with a computer or external software. So, we are going to use Analog Discovery 2 which is a portable and compact all-in-one measurement system.

Analog Discovery 2:

Analog Discovery 2 is a versatile circuit learning platform that can fit in your pocket and costs less than a textbook. It can measure, visualize, analyze, record, and control mixed signal circuits using the Hi-Speed USB port and the free WaveForms software. Whether you are working in the lab or outside, you can build and test analog and digital circuits with ease and convenience.

Analog Inputs:

• Channels: 2
• Channel type: differential
• Resolution: 14-bit
• Sample rate (real-time): 100 MS/s
• Input range: ±25V (±50V diff)
• Input protected to: ±50V
• Buffer size/channel: Up to 16k samples
• Triggering: edge, pulse, transition, hysteresis, etc.
• Cross-triggering with Logic Analyzer, Waveform Generator, Pattern Generator, or external trigger
• Mixed signal visualization (analog and digital signals share thesame view pane)
• Real-time views: FFTs, XY plots, histograms, and other
• Multiple math channels with complex functions
• Cursors with advanced data measurements
• Captured data files can be exported in standard formats
• Scope configurations can be saved, exported, and imported

Arbitrary Waveform Generator:

• Channels: 2
• Channel type: single ended
• Resolution: 14-bit
• Sample rate (real time): 100 MS/s
• AC amplitude (max): ±5 V
• DC Offset (max): ±5
• Slew rate (10V step): 400V/µs
• Buffer size/channel: up to 16k samples
• Standard waveforms: sine, triangle, sawtooth, etc.
• Advanced waveforms: Sweeps, AM, FM.
• User-defined arbitrary waveforms: defined within WaveForms software user interface or using standard tools (e.g. Excel)

Logic Analyzer:

• Channels: 16 (shared)
• Sample rate (real time): 100 MS/s
• Buffer size/channel: up to 16K samples
• Input logic: LVCMOS (1.8V/3.3V, 5V tolerant)
• Multiple trigger options including pin change, bus pattern, etc.
• Cross-triggering between Analog input channels, Logic Analyzer, Pattern Generator, or external trigger
• Interpreter for SPI, I2C, UART, Parallel bus
• Data file import/export using standard formats

Digital Pattern Generator:

• Channels: 16 (shared)
• Sample rate (real time): 100 MS/s
• Algorithmic pattern generator (no buffers used)
• Custom pattern buffer/channel: up to 16K samples
• Output logic standard: LVCMOS (3.3V, 12mA)
• Data file import/export using standard formats
• Customized visualization for signals and buses

Digital I/O:

• Channels: 16 (shared)
• Input logic: LVCMOS (1.8V/3.3V, 5V tolerant)
• Output logic standard: LVCMOS (3.3V, 12mA)
• Virtual I/O devices (buttons, switches & displays)
• Customized visualization options available

Power Supplies:

• Voltage range: 0.5V…5V and -0.5V…-5V
• Pmax (USB powered): 500mW total
• Pmax (AUX powered): 2.1W for each supply
• Imax (AUX powered): 700mA for each supply
• Accuracy (no load): ±10mV

Network Analyzer:

• Shared instruments: Scope, AWG
• Frequency sweep range: 1Hz to 10MHz
• Frequency steps: 5 … 1000
• Settable input amplitude and offset
• Analog input records response at each frequency
• Available diagrams: Bode, Nichols, or Nyquist

Voltmeters:

• Channels (shared with scope): 2
• Channel type: differential
• Measurements: DC, AC, True RMS
• Resolution: 14-bit
• Input impedance: 1MΩ || 24pF
• Input range: ±25V (±50V div)
• Input protected to: ±50V

Spectrum Analyzer:

• Channels (shared with scope): 2
• Power spectrum algorithms: FFT, CZT
• Frequency range modes: center/span, start/stop
• Frequency scales: linear, logarithmic
• Vertical axis options: voltage-peak, voltage-RMS, dBV, and dBu
• Windowing: options: rectangular, triangular, hamming, Cosine, and many others
• Cursors and automatic measurements: noise floor, SFDR, SNR, THD and many others
• Data file import/export using standard formats

Other Features:

• USB power option; all needed cables included.
• External supply option: 5V, 2.5A (not included)
• High-speed USB2 interface for fast data transfer
• Waveform Generator output played on stereo audio jack
• Trigger in/trigger out allows multiple instruments to be linked
• Cross triggering between instruments
• Help screens, including contextual help
• Instruments & workspaces can be individually configured; configurations can be exported
• Device drivers available for NI LabVIEW

You can just use the Waveforms software to control and measure via AD2.

In AD2 you can't measure the current directly, you have to do some workarounds to do that. So, I planned to use another one tool to do that.

Power Profiler Kit II:

The Power Profiler Kit II (PPK2) is a standalone unit, which can measure and optionally supply currents all the way from sub-uA and as high as 1A on all Nordic DKs, in addition to external hardware.

An ampere meter-only mode, as well as a source mode (shown as AMP and source measure unit (SMU) respectively on the PCB), are supported. For the ampere meter mode, an external power supply must source VCC levels between 0.8 and 5V to the device under test (DUT). For the source mode, the PPK2 supplies VCC levels between 0.8 and 5V and the on-board regulator supplies up to 1A of current to external applications. It is possible to measure low sleep currents, higher active currents, as well as short current peaks on all Nordic DKs, in addition to external hardware.

Key Features:

• 200nA to 1A measurement range
• Resolution varies between 100nA and 1mA depending on the measurement range
• Support for all Nordic DKs, in addition to custom HW
• Ampere meter and source modes
• 10x quicker sampling (100ksps) vs previous generation
• Standalone unit
• 0.8 - 5V VCC levels
• 8 digital inputs enable low-end logic analyzer support

We can connect the PPK2 with LattePanda 3 Delta via the nRF Connect application,

also we have some open-sourced Python libraries to control the PPK2 to do some automation.

GitHub - IRNAS/ppk2-api-python: Power Profiling Kit 2 unofficial python api.

Control System:

So, now we have all our instrument, inorder to automate the measurements. We need some automation software to initialte measurement and data analysis. For that purpose we are going to use the LabView software which can able to control instruments and capture data based on user commands.

LabVIEW is a graphical programming environment engineers use to develop automated test systems for various applications that require data acquisition, analysis, and control. It was created by National Instruments and is widely used in industries such as aerospace, automotive, biotechnology, communications, and education.

LabVIEW simplifies hardware integration and provides a consistent way to acquire data from NI and third-party hardware. It also allows you to create interactive user interfaces for test monitoring and control, and to integrate code written in Python, C/C++,.NET, and MathWorks MATLAB® software.

Wrap Up:

That's all about the first part, now we have all our instruments and the control system. We can start building on the system. In upcommig tutorials, will start to install the LabView on the LattePanda 3 Delta and let's do some basic sutomation.