Usage

Create python virtual enviroment, if not already created

python -m venv bddAqEnv

Activate python venv

.\bddAqEnv\Scripts\activate.bat 

Install dependencies, if not already installed

pip install -r requirements.txt

Connect BDD board using UART and run the app using commandline

python __main__.py -p COM11 -1 0 -2 1 -1p 2000 -2p 4 -1f 1 -2f 100 -1d 50 -2d 50 -fs 7000 -o data.csv 

REQUIRED command line parameters

• -p --port COM port to use
• -1 --ch1_en Channel 1 enable (0 or 1)
• -2 --ch2_en Channel 2 enable (0 or 1)
• -1p --ch1_polarity Channel 1 polarity change interval - seconds
• -2p --ch2_polarity Channel 2 polarity change interval - seconds
• -1f --ch1_pwmFreq Channel 1 PWM frequency (0 disables PWM) - Hz
• -1f --ch1_pwmFreq Channel 2 PWM frequency (0 disables PWM) - Hz
• -1d --ch1_pwmDuty Channel 1 PWM duty (0 disables channel, 100 disables PWM) - %
• -2d --ch2_pwmDuty Channel 2 PWM duty (0 disables channel, 100 disables PWM) - %
• -fs --sampleFreq Measurement sampling frequency, should be at least 2*PWM frequency - Hz

OPTIONAL command line parameters

• -o --output Name of CSV file to which measured data will be written. If not specified, logging is disabled.

Logging

App is logging data to specified file in CSV format with this header

"Timestamp", "CH1 Current (A)", "CH1 Voltage (V)", "CH1 Total charge (C)", "CH2 Current (A)", "CH2 Voltage (V)", "CH2 Total charge (C)"

GUI

App has a simple gui available at http://localhost:8050
Datas are refreshed every second. Values shown are an averaged values from last 1 second. Delta indicators show difference against long term average of last 10 seconds.

Specialitky

When channel is left floating (no load connected, or high impedance), it should be disabled using -1 or -2 parameter. If floating channel is not disabled, measurements will be saturated with noise.

Maximum sampling frequency is 7 kHz, maximum PWM frequency is 562.5 kHz, maximum polarity change interval should be 65535 seconds. Duty cycle has resolution of 0.78 %

Maximum measured voltage is +-60V, with 10% offset error - real range is therefore approximately +-54V. Voltage is measured at the output so it will follow polarity change interval.
Maximum measured current is by default 10 A.

Resolution of both measurements is 16 bit, that is 1.8 mV for voltage and 0.15 mA for current. However noise is a significant factor, therefore reported values will have accuracy of +- 5%, if properly calibrated.

Offsets are calibrated automatically at every boot, values are mapped by predefined mapping transfer functions based on prototype device.