pymacnet 1.1.3

A class based python interface for communication and control of Maccor cyclers over Macnet.

pymacnet

pymacnet is a Python module that provides cycler and channel level interfaces for communication and control of Maccor cyclers via MacNet. MacNet is an interface provided by Maccor that allows for controlling their cyclers via UDP/IP and TCP/IP. pymacnet provides a hassle-free way to utilize MacNet with a simple python class.

Overview

• Motivation
• Installation
  • Requirements
  • Installation Instructions
• Examples
  • Getting Started
    • CyclerInterface Configuration
    • ChannelInterface Configuration
  • Getting Cycler Level Information
  • Getting Channel Readings
  • Starting a Test
  • Setting Variables
  • Direct Control
• Development
  • Contributing
  • Testing
    • MaccorSpoofer
  • Documentation
• License

Motivation

Why did we create pymacnet? This package enables a wide variety of applications such as:

• Real-time data logging, monitoring and alerting

pymacnet can be used to passively monitor running tests and log readings directly to a database, bypassing the need to manually export data. Moreover, it's possible to create automated alerts based on incoming real-time data. For example, if a test were to fault or temperature were to exceed a set threshold. While Maccor already has a built-in notification system with MacNotify, pymacnet provides a more flexible and customizable solution without having to directly modify test procedures.

• Automated test management

The GUI provided by Maccor for test management is straight-forward and easy to use, but requires significant manual work. With pymacnet it is possible to write programs to automatically start tests simultaneously across many channels (or even many cyclers) at once.

• Testing of next generation closed-loop charging methods

While conventional constant-current followed by constant-voltage (CCCV) charging has been the industry standard for many years and is well supported by cyclers, there is movement towards advanced closed-loop control charging techniques that provide improved battery life and decreased charge times. pymacnet enables testing of closed-loop battery charging methods by providing an interface between software hosting battery charging algorithms and active Maccor tests, allowing the charge current to be dynamically set.

• Well tested, easy to use, community supported interface in the most popular programming language.

It is entirely possible to write one's own MacNet wrapper, but pymacnet provides a well-tested ready to use package that takes care of lower level communication, providing a simple yet powerful interface in the most popular programming language.

Installation

Requirements

pymacnet requires only Python 3 and packages from the standard library. It has been tested on on Windows, Mac, and Debian operating systems.

Installation Instructions

Install pymacnet using pip:

pip install pymacnet

Install pymacnet from source code:

git clone https://github.com/BattGenie/pymacnet.git
cd pymacnet
pip install -r requirements.txt
pip install .

Examples

This section goes over various examples of how to use pymacnet to do such tasks as getting channel readings, starting a test, and even controlling a channel directly without a test procedure. For interactive examples see the demo.ipynb notebook in the repository.

Getting Started

pymacnet provides two classes for interacting with a Maccor cycler:

• CyclerInterface Provides a cycler level interface. The class instance allows for reading cycler level information, such as system software and configuration information, and statuses of all channels.

• ChannelInterface Provides a channel level interface for a specific channel on the cycler. ChannelInterface is a child class of CyclerInterface so all the same cycler level methods are available, but with ChannelInterface it's possible to read more detailed information about a channel and even even control it. Each class instance targets a specific channel of the cycler.

CyclerInterface Configuration

The fields required in a CyclerInterface configuration dictionary are as follows:

• server_ip - The IP address of the Maccor server. Use 127.0.0.1 if running on the same machine as the server.
• json_msg_port - The port to communicate through with JSON messages. Default set to 57570.
• bin_msg_port - The port to communicate through with binary messages. Default set to 57560.
• msg_buffer_size_bytes - How big of a message buffer to use for sending/receiving messages. A minimum of 1024 bytes is recommended.

ChannelInterface Configuration

The fields required in a ChannelInterface configuration dictionary are as follows:

• server_ip - The IP address of the Maccor server. Use 127.0.0.1 if running on the same machine as the server.
• json_msg_port - The port to communicate through with JSON messages. Default set to 57570.
• bin_msg_port - The port to communicate through with binary messages. Default set to 57560.
• msg_buffer_size_bytes - How big of a message buffer to use for sending/receiving messages. A minimum of 1024 bytes is recommended.
• channel - The channel to be targeted for all operations.
• test_name - The test name to be used for any tests started. If left blank, Maccor will generate a unique random name for any started tests. Note that Maccor requires unique test names for each test.
• test_procedure - The test procedure to be used, if starting a test with a procedure. Not needed with direct control.
• c_rate_ah - The capacity value to be referenced when setting "C" values within the Maccor schedule. Units of amp-hours. Ignored if not used anywhere in the test.
• v_max_safety_limit_v - Upper voltage safety limit for the channel. Units of volts.
• v_min_safety_limit_v - Lower voltage safety limit for the channel. Units of volts.
• i_max_safety_limit_a - Upper current safety limit for the channel. Units of amps.
• i_min_safety_limit_a - Lower current safety limit for the channel. Units of amps.
• power_safety_limit_chg_w - The power safety limit for charge. Units of watts.
• power_safety_limit_dsg_w - The power safety limit for discharge. Units of watts.
• v_max_v - Upper voltage limit used for charge/CV limits. Units of volts. Only used with direct control.
• v_min_v - Lower voltage limit used for discharge limit. Units of volts. Only used with direct control.
• data_record_time_s - How often data points are taken during direct control tests. Zero turns off. Used only for direct control.
• data_record_voltage_delta_vbys - The dV/dt at which data points are taken during direct control tests. Zero disables. Used only for direct control.
• data_record_current_delta_abys - The dI/dt at which data points are taken during direct control tests. Zero disables. Used only for direct control.

Getting Cycler Level Information

Here is some example code for getting cycler level readings with the CyclerInterface class.

import time
import sys
import pymacnet 

config = {
    "server_ip": "127.0.0.1",
    "json_msg_port": 57570,
    "bin_msg_port": 57560,
    "msg_buffer_size_bytes": 1024
}
    
cycler_interface = pymacnet.CyclerInterface(config)
if not channel_interface.start():
    sys.exit("failed to create connection!")

system_info = cycler_interface.read_system_info()
print(system_info)

general_info = cycler_interface.read_general_info()
print(general_info)

channel_statuses = cycler_interface.read_all_channel_statuses()
print(channel_statuses)

Example output:

{'FClass': 1, 'FNum': 1, 'APIVersion': 1, 'MacTest32EXEversionMajor': 3, 'MacTest32EXEversionMinor': 2, 'MacTest32EXEversionBuild': 18 'MacTest32DLLversionMajor': 3, 'MacTest32DLLversionMsinor': 2, 'MacTest32DLLversionBuild': 18, 'MacTest32ExeDT': '2016-11-08T15:02:58', 'MacTest32DLLDT': '2016-11-13T11:29:48'}

{'FClass': 1, 'FNum': 2, 'SystemID': 'Win10', 'SystemType': 0, 'ControllerBoards': 3, 'TestChannels': 12, 'AuxBoards': 1, 'AuxChannels': 128, 'SMB1Pos': 0, 'SMB3Pos': 1}

[{'RF1': 0, 'RF2': 0, 'Stat': 0}, {'RF1': 0, 'RF2': 0, 'Stat': 0}]

Getting Channel Readings

Below is example code for reading channel status (which includes voltage, current, etc.) from channel 75.

import time
import sys
import pymacnet 

config = {
    "server_ip": "127.0.0.1",
    "json_msg_port": 57570,
    "bin_msg_port": 57560,
    "msg_buffer_size_bytes": 1024
    "channel": 75,
    "test_name": "",
    "c_rate_ah": 1,
    "v_max_v": 4.2,
    "v_min_v": 3.0,
    "v_max_safety_limit_v": 4.25,
    "v_min_safety_limit_v": 2.9,
    "i_max_safety_limit_a": 3.0,
    "i_min_safety_limit_a": 3.0,
    "power_safety_limit_chg_w": 25,
    "power_safety_limit_dsg_w": 25,
    "data_record_time_s": 0.05,
    "data_record_voltage_delta_vbys": 0.0,
    "data_record_current_delta_abys": 0.0,
    "test_procedure": "test_procedure_1",
}
    
channel_interface = pymacnet.ChannelInterface(config)
if not channel_interface.start():
    sys.exit("failed to create connection!")

status_reading = channel_interface.read_channel_status()
print(status_reading)

Example output:

{'FClass': 4, 'FNum': 7, 'Chan': 1, 'RF1': 0, 'RF2': 192, 'Stat': 0, 'LastRecNum': 4225, 'Cycle': 0, 'Step': 5, 'TestTime': 2.0, 'StepTime': 1.0, 'Capacity': 0, 'Energy': 0, 'Current': 0, 'Voltage': 3.85, 'TesterTime': '2022-10-13T12:32:56'}

Starting a Test

Here is in example of how to start a test named "simple_test_1" on channel 75 with an existing test procedure named "test_procedure_1". Note the safety limits defined in the config will be set on the channel before starting the test. Also, test names must be unique. If a non-unique test name is provided then the test will not start. If no test name is provided then a unique random test name is generated.

import pymacnet
import sys

config = {
    "server_ip": "127.0.0.1",
    "json_msg_port": 57570,
    "bin_msg_port": 57560,
    "msg_buffer_size_bytes": 1024
    "channel": 75,
    "test_name": "simple_test_1",
    "c_rate_ah": 1,
    "v_max_v": 4.2,
    "v_min_v": 3.0,
    "v_max_safety_limit_v": 4.25,
    "v_min_safety_limit_v": 2.9,
    "i_max_safety_limit_a": 3.0,
    "i_min_safety_limit_a": 3.0,
    "power_safety_limit_chg_w": 25,
    "power_safety_limit_dsg_w": 25,
    "data_record_time_s": 0.05,
    "data_record_voltage_delta_vbys": 0.0,
    "data_record_current_delta_abys": 0.0,
    "test_procedure": "test_procedure_1",
}
channel_interface = pymacnet.ChannelInterface(config_dict)
if not channel_interface.start():
    sys.exit("failed to create connection!")

if channel_interface.start_test_with_procedure():
    print("Test started!")

Setting Variables

Here is an example of how to set VAR1 to 0.01 on a test running on channel 75.

import pymacnet
import sys

config = {
    "server_ip": "127.0.0.1",
    "json_msg_port": 57570,
    "bin_msg_port": 57560,
    "msg_buffer_size_bytes": 1024
    "channel": 75,
    "test_name": "",
    "c_rate_ah": 1,
    "v_max_v": 4.2,
    "v_min_v": 3.0,
    "v_max_safety_limit_v": 4.25,
    "v_min_safety_limit_v": 2.9,
    "i_max_safety_limit_a": 3.0,
    "i_min_safety_limit_a": 3.0,
    "power_safety_limit_chg_w": 25,
    "power_safety_limit_dsg_w": 25,
    "data_record_time_s": 0.05,
    "data_record_voltage_delta_vbys": 0.0,
    "data_record_current_delta_abys": 0.0,
    "test_procedure": "test_procedure_1",
}

channel_interface = pymacnet.ChannelInterface(config_dict)
if not channel_interface.start():
    sys.exit("failed to create connection!")

channel_interface.set_channel_variable(var_num = 1, var_value = 0.01)

Direct Control

Here is an example of how to bypass using a test procedure all together and control the channel directly using direct control. Note the channel safety limits will be set before the test is started. WARNING DIRECT CONTROL IS POTENTIALLY DANGEROUS. BE CAREFUL AND MAKE SURE YOU UNDERSTAND EXACTLY WHAT YOUR CODE IS DOING.

import pymacnet
import sys

config = {
    "server_ip": "127.0.0.1",
    "json_msg_port": 57570,
    "bin_msg_port": 57560,
    "msg_buffer_size_bytes": 1024
    "channel": 75,
    "test_name": "",
    "c_rate_ah": 1,
    "v_max_v": 4.2,
    "v_min_v": 3.0,
    "v_max_safety_limit_v": 4.25,
    "v_min_safety_limit_v": 2.9,
    "i_max_safety_limit_a": 3.0,
    "i_min_safety_limit_a": 3.0,
    "power_safety_limit_chg_w": 25,
    "power_safety_limit_dsg_w": 25,
    "data_record_time_s": 0.05,
    "data_record_voltage_delta_vbys": 0.0,
    "data_record_current_delta_abys": 0.0,
    "test_procedure": "test_procedure_1",
}

channel_interface = pymacnet.ChannelInterface(config_dict)
if not channel_interface.start():
    sys.exit("failed to create connection!")

if channel_interface.start_test_with_direct_control():
    print("Test started!")
else:
    sys.exit("Failed to start test!")

time.sleep(1) # Must wait at least 100 ms between trying to set control

# Discharge at 200 mA for 5 seconds. 
channel_interface.set_direct_mode_output(current_a = -0.200)
time.sleep(5)

# Rest for 5 seconds
channel_interface.set_direct_mode_output(current_a = 0)
time.sleep(5) 

# Charge at 200 mA for 5 seconds
channel_interface.set_direct_mode_output(current_a = 0.200)
time.sleep(5)

channel_interface.set_direct_mode_output(current_a = 0.0)
time.sleep(1)

Development

This section contains various information to help developers further extend and test pymacnet

Contributing

As it exists now, pymacnet only implements a fraction of the messages supported by MacNet. Further work can be done to expand pymacnet to include more of the messages detailed in the MacNet documentation docs/macnet_from_maccor_help.pdf.

We welcome your help in expanding pymacnet! Please see the CONTRIBUTING.md file in this repository for contribution guidelines.

Testing

To run the tests navigate to the "tests" directory and type the following:

pytest .

MaccorSpoofer

Testing software on a real cycler is dangerous so we've created a submodule maccorspoofer to emulate some of the behavior of the Maccor software with a class MaccorSpoofer. This class creates TCP and UDP servers and accepts connections from n number of clients. The MaccorSpoofer does not perfectly emulate a Maccor cycler (for example, it does not track if a test is already running on a channel) and merely checks that the message format is correct and responds with standard message. Example usage of MaccorSpoofer is documented in the file demo_maccorspoofer.ipynb and a video demonstration for the same can be found here.

Documentation

All documentation was generated with pydoc. To re-generate the documentation type the following command from the top level directory of the repository:

pydoc --html .

License

MIT License

Copyright (c) 2024 BattGenie Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE