Advanced PID Controller for Node-RED

This project provides a versatile and user-friendly PID (Proportional-Integral-Derivative) controller package for Node-RED. It began as a fork of node-red-contrib-easy-pid-controller and has been significantly enhanced with advanced features for more flexible process control.

The package includes the main Advanced PID Controller node and several Companion Nodes to make building control flows intuitive and clean, especially for beginners.

Features

• Multiple Operational Modes: Switch between Auto, Manual, and Off modes on the fly.
• Auto Mode Enable: A dedicated input to pause or resume the controller while in Auto mode, useful for multi-device coordination.
• Advanced PID Settings: Includes Deadband configuration to prevent output oscillation around the setpoint.
• Anti-Windup: The controller's output is clamped between configurable minimum and maximum limits.
• Dedicated Outputs: The node features three separate outputs for the full status object, a simple boolean "enable" signal, and the direct analog output value.
• Companion Nodes: A set of helper nodes to provide clear, topic-free inputs for Setpoint (SV), Process Value (PV), Mode, Manual Value, and Auto Enable.
• Easy Configuration: All PID parameters (Kp, Ki, Kd), timing, and limits are easily configured in the node's editor.

Installation

Run the following command in your Node-RED user directory (typically ~/.node-red):

npm install node-red-contrib-advanced-pid-controller

Usage

This package contains multiple nodes that appear in the function category of the palette.

1. The Main Controller

The core of the package is the advanced-pid-controller node. Configure its PID parameters in the properties dialog. This node receives all inputs via messages with specific topics.

2. Companion Nodes (Recommended)

For easier and more readable flows, use the companion nodes to feed data into the main controller:

• Setpoint (SV): Feeds a numerical payload as the controller's setpoint.
• Process Value (PV): Feeds a numerical payload as the current process value.
• Mode: Feeds a numerical payload (0, 1, or 2) to set the operational mode.
• Manual Value: Feeds a numerical payload as the output value for manual mode.
• Auto Enable: Feeds a boolean payload to pause or resume the controller in auto mode.

A typical flow looks like this:

[Inject SV]  --> [Setpoint (SV)]    \
[Sensor Data]--> [Process Value (PV)] -- > [advanced-pid-controller] --> Outputs...
[Select Mode]--> [Mode]             /
[Enable Logic]-> [Auto Enable]      /

Node Reference

advanced-pid-controller

Inputs

The node accepts messages with the following msg.topic values:

• mode (integer): Sets the operational mode:
  • 0: Auto - The PID controller is active.
  • 1: Manual - The output is manually set by the manualValue input.
  • 2: Off - The controller is inactive, output is 0, and enable is false.
• autoEnable (boolean): When in Auto mode, this input controls the controller's state. If true (default), the controller runs. If false, the controller pauses, resets, and sets its outputs to 0 and false.
• PV (number): The current Process Value (e.g., the sensor reading).
• SV (number): The desired Setpoint Value for the controller.
• manualValue (number): The value to output when the controller is in Manual mode.

Outputs

The node has three outputs:

1. Full Status (object): Sends a message object containing the controller's complete state ({PV, SV, P, I, D, Output}).
2. Digital Enable (boolean): Sends true if the mode is Auto (and enabled) or Manual. Sends false if the mode is Off or if Auto mode is paused.
3. Analog Value (number): Sends a simple message with the final output value as the msg.payload.

Companion Nodes

• Setpoint (SV)
• Process Value (PV)
• Mode
• Manual Value
• Auto Enable

Each companion node takes any msg.payload as input, sets the appropriate msg.topic, and passes the message on. They require no configuration.

Contributing

Contributions to improve the node or fix any issues are always welcome. Please submit a pull request on the GitHub repository.

License

This project is licensed under the GPL-3.0 License. See the LICENSE file for details.

Author

• Marc Alzen (@MarAlze)

Original Author

This project is a fork of node-red-contrib-easy-pid-controller, originally created by Harshad Joshi.