PID controller GUI

Features

• Get and set PID parameters:
  • Setpoint
  • kP, kI and kD coefficients
  • Limits of proportional & integral components errors
  • Reset accumulated integral error
• Monitor process variable and controller output through live graphs @ 60 FPS
• Save PID parameters to the controller' non-volatile memory
• Demo mode: activates when no network connection established

Overview

The application is supposed to connects to some kind of bare-metal MCU or OS-based controller that uses a proportional-integral-derivative algorithm as a core to drive some parameter in physical system. PID is a generic efficient-proven method for such tasks, find more about it in topic resources.

It can be used as a general tool to help:

• Setup and adjust the PID regulator for the first time
• Monitor its stability during a long operation
• Diagnose and find issues

Main advantage of the dedicated interface is the ability to establish a connection of any type while not changing the behavior of other logic. For example, current active UDP/IP stack can be replaced by a serial UART protocol and so on. The application does not contain any hard-coded specific definitions that allows to assign them by an end-user.

Architecture

Besides modular structure the app also applies multithreaded approach to split resources on different tasks. For example, in communication protocol (described in INSTRUCTIONSET) 2 types of messages are defined: 'normal' and stream. Normal variables/commands are delivering by demand, using request/response semantics. In contrast, stream messages are constantly pouring from the controller so the client should plot them onto graph. Such scene is perfectly lays on the concept of dedicated input listening thread that concurrently runs alongside the main thread and redirect incoming messages according to their type. It is implemented through multiprocessing API (processes and pipes).

For detailed description on particular things please refer to in-code documentation.

remotecontroller.py

This file provides communication interface from/to remote controller. It has zero external dependencies (only Python standard library) and therefore can, in general, be used in any, perhaps non-GUI, applications.

Simulator

For debug and development purposes the PID regulator simulator has been created. It is a C-written UDP server implementing the same instruction set interface so it acting as a real remote controller. See pid-controller-server for more information.

Dependencies

• Python 3
• PyQt5
• PyQtGraph
• qdarkstyle (provides dark theme)
• [optional] PyInstaller (provides packing into bundle)

Usage

Run

pid-controller-gui/pid-controller-gui $ python3 main.py

Default settings are located in defaultSettings.json file and currently available only in non-bundled mode. Different timeouts are placed directly in modules' code and so also can be edited only programmatically.

Packing into standalone app

It is possible to bundle the application into a standalone executable using PyInstaller. See respective README in pyinstaller folder.

UML

You can find a sketch diagram in uml folder (created in draw.io).