P1125 Online Help

P1125 Online Help

p1125_scripts

The P1125 can be automated using its JSON-RPC interface. This repo shows Python examples of the JSON-RPC API.

The example scripts use a Python class in P1125.py that makes it easy to use the JSON-RPC API, as if the API were just typical Python class function calls.

Instillation

• Install Python 3.6 (or greater)

• Install your favorite Python IDE, for example PyCharm

• Clone this repo

• Install python requirements from requirements.txt

  pip3 install -r requirements.txt

Getting Started

• The JSON_RPC API requires the IP address, or hostname of the P1125.
• All the example scripts have a section that looks like this,

    # NOTE: Change to P1125 IP address or hostname
    P1125_URL = "p1125-####.local"  # for example, p1125-a12b.local, or 192.168.0.123
    
    if "p1125-####.local" in P1125_URL:
        logger.error("Please set P1125_URL with valid IP/Hostname")
        exit(1)

• p115-####.local needs to be changed to reflect the P1125 IP address or hostname of your device.
• The hostname of the P1125 is written on the bottom of the device, in the format p1125-####.local.
• Or if the IP address is known, that may be used.

    P1125_URL = "192.168.0.123"

• Testing your P1125 connection

  • Start with the p1125_example_ping.py script. This script will simply ping your P1125.

  • Update P1125_URL as described above.

  • Example output,

    /usr/bin/python3.6 /home/martin/git/p1125_scripts/p1125_example_ping.py
    2021-07-19 13:05:56,688:       ping  217 - INFO  : V1.ping http://192.168.86.24:6590/api/V1
    2021-07-19 13:05:56,712:       main   73 - INFO  : {'success': True, 'version': 'Ver0.4-31', 'rpi_serial': '1000000062fc4808', 'url': 'p1125-419b', 'a10_serial': '2e0052000d50533742393220', 'a10_hw_ver': 2686519040, 'a10_bom': 4294967295, 'mac_eth0': 'dc:a6:32:6a:41:9b', 'mac_wlan0': 'dc:a6:32:6a:41:9c'}
    2021-07-19 13:05:56,712:     status  222 - INFO  : V1.status
    2021-07-19 13:05:56,727:       main   77 - INFO  : {'success': True, 'version': 'Ver0.4-31', 'cal_done': False, 'aqc_in_progress': False, 'temperature_degc': 34, 'error': [], 'error_action': []}
    
    Process finished with exit code 0
    

  • This confirms you can access the P1125 remotely.

• You may then try the other scripts, and/or copy one of them and modify for your use.

  • python3 p1125_example_plot_cal_loads.py
    • Example of how to pull real time plot data.
    • The example uses the internal CAL loads, but can be modified to use target data.
  • p1125_example_mahrs.py
    • Script that plots the mAhrs versus VOUT.
    • This example shows how your target current changes with Battery voltage. Battery voltage changes as the battery is drained, and the efficiency of your target buck/boost converters will change with changing input voltage.

Plotting Results

The scripts use open source plotting framework bokeh, https://docs.bokeh.org/en/latest/index.html

Long Time Logging Script

The (example) script p1125_example_mahrs_logging.py is provided as an example on how to take long time (hours, days, etc) measurement logs. The companion script p1125_example_mahrs_logging_plot.py plots the data.

The measurement data for long time logs comes from the "mAhr" data stream of the P1125. This stream is averaged measurement data from the real time P1125 data acquisition path. The P1125 sampling rate is always 48kHz (20.83 usec). The "mAhr" stream takes these samples and integrates them over a 10ms window (480 samples) to determine the average for that window. Fast events within the 10ms window are of course included in this average Because the sample rate is maintained at 48KHz. This averaging is done to reduce the amount of data to process when dealing with long time plots/logs. Also, the peak current within the 10ms window is also recorded and is plotted in the example script.

There are two main parameters to set up for a long term log,

• TIME_CAPTURE_WINDOW_S
  • This represents the total time to take 10ms samples.
  • A resonable value for this is 60 (seconds). This will result in up to ~4k samples per capture window.
• TIME_TOTAL_RUN_S
  • This sets the total run time.

These, and other, parameters are set at the top of the script,

# Change these parameters to suit your needs:
VOUT = 3000                   # mV, output voltage, 1800-4500 mV
CONNECT_PROBE = False         # set to True to attach probe, !! Warning: check VOUT setting !!
TIME_CAPTURE_WINDOW_S = 60    # seconds over which to measure the AVERAGE mAhr
TIME_TOTAL_RUN_S = TIME_CAPTURE_WINDOW_S * 5   # seconds, total run time of the log
LOG_FILE_PATH = "./"          # path to output file (filename is generated)

The logging script will generate a python file with the measurement data. This log file name is a date stamp. An example of such a file is shown here,

# This file is auto-generated by p1125_example_mahrs_logging.py                                                                                                                                                            
# 20201116-135355.py                                                                                                                                                                                                   
p1125_ping = {'success': True, 'version': 'Ver0.3-250', 'rpi_serial': '1000000062fc4808', 'url': 'p1125-419b', 'a10_serial': '390032000e504e4856333420', 'a10_hw_ver': 2685408000, 'a10_bom': 4294967295}              
p1125_status = {'success': True, 'version': 'Ver0.3-250', 'cal_done': True, 'aqc_in_progress': False, 'temperature_degc': 25, 'error': [], 'error_action': []}                                                         
p1125_settings = {'VOUT': 1500, 'TIME_CAPTURE_WINDOW_S': 60, 'TIME_TOTAL_RUN_S': 300, 'CONNECT_PROBE': False}                                                                                                          
# NOTE: Might have to add missing last ']' if program was interrupted                                                                                                                                                  
p1125_data = [                                                                                                                                                                                                         
{'datetime': '20201116-135501', 'time_s': 63.24122, 'mAhr': 0.7496259, 'samples': 40,'plot': {'t': [0, 5.640928, 5.654016, 5.667104, 5.680192, 5.69328, 5.706368, 5.745632, 5.75872, 5.771808, ...
{'datetime': '20201116-135605', 'time_s': 63.24122, 'mAhr': 0.7488481, 'samples': 36,'plot': {'t': [0, 1.989376, 2.002464, 2.015552, 2.15952, 2.172608, 2.185696, 2.198784, 2.211872, 2.264224, ...
{'datetime': '20201116-135708', 'time_s': 63.24122, 'mAhr': 0.7486486, 'samples': 26,'plot': {'t': [0, 15.78413, 15.8103, 19.7367, 19.76288, 23.68928, 23.71546, 27.64186, 27.66803, 31.59443, ...
{'datetime': '20201116-135811', 'time_s': 63.24122, 'mAhr': 0.7484611, 'samples': 26,'plot': {'t': [0, 15.78413, 15.8103, 19.7367, 19.76288, 23.68928, 23.71546, 27.64186, 27.66803, 31.59443, ...
{'datetime': '20201116-135915', 'time_s': 63.24122, 'mAhr': 0.748446, 'samples': 26,'plot': {'t': [0, 15.78413, 15.8103, 19.7367, 19.76288, 23.68928, 23.71546, 27.64186, 27.66803, 31.59443,  ...
]                                                                                                                                                                                                                                                                                                                                                                                                                                             

The example script sets up a 2K Ohm load at 3000mV VOUT, so the expected current is ~750uA. Because this test load is constant, there isn't much interesting to see, and note the number of samples is greatly reduced because the load was static.

The plotting tool is executed through the bokeh server because it is an interactive tool. The plotting script is executed in this way, from a command prompt,

$ bokeh serve --show p1125_example_mahrs_logging_plot.py --args -f 20201116-135355.py

Where the logging filename, 2020116-135355.py will be specific to you.

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