Add & remove devices to group dynamically

NDU PE Feature Only NDU Professional Edition supports Device & Asset Groups feature. See NDU PE Installation Options to install NDU PE.

This tutorial will show how to dynamically add & remove device from the device group based on incoming data from device.

• Use case
• Prerequisites
• Model definition
• Message Flow
  • Root rule chain
  • New “Add device to group” rule chain
• Configuring the Rule Chain
• Validating the flow
• Next steps

Use case

Let’s assume your device is reporting temperature readings to NDU and you would like to visualize devices that have reported temperature > 50°C.

In this tutorial we will configure NDU Rule Engine to automatically update “High temperature devices” group members based on incoming temperature readings from the device. You can use this tutorial as a basis for much more complex filtering.

Prerequisites

We assume you have completed the following guides and reviewed the articles listed below:

• Getting Started guide.
• Rule Engine Overview.

Model definition

We will operate with Temperature sensor device that has name “Sensor A” and type “DHT22”.

Message Flow

In this section, we explain the purpose of each node in this tutorial.

Root rule chain

• Node A: Rule Chain node

  • We modify the default root rule chain to forward all telemetry to new “Add device to group” rule chain

New “Add device to group” rule chain

• Node B: Script filter node

  • Checks that the incoming message from device contains temperature readings
  • If message from device contains temperature readings it is forwarded to Node C

• Node C: Script filter node

  • Checks that the incoming message temperature is > 50°C
  • If temperature > 50°C message is forwarded to Node D
  • If temperature <= 50°C message is forwarded to Node E

• Node D: Add to Group node

  • Adds device to the group
  • Constructs group name by substituting deviceType metadata value
  • Automatically creates device group if needed

• Node E: Remove from Group node

  • Removes device from the group
  • Constructs group name by substituting deviceType metadata value

Configuring the Rule Chain

Download and import attached json file as a new “Add device to group” rule chain. Please note that all nodes have debug enabled. This affects performance. Create Node A as shown on the image above in the root rule chain to forward telemetry to new rule chain.

Validating the flow

Publish temperature readings on behalf of the new device and observe new group automatically created:

Next steps

• Getting started guides - These guides provide quick overview of main NDU features. Designed to be completed in 15-30 minutes.

• Installation guides - Learn how to setup NDU on various available operating systems.

• Connect your device - Learn how to connect devices based on your connectivity technology or solution.

• Data visualization - These guides contain instructions how to configure complex NDU dashboards.

• IoT Data analytics - Learn how to use rule engine to perform basic analytics tasks.

• Hardware samples - Learn how to connect various hardware platforms to NDU.

• Advanced features - Learn about advanced NDU features.