What is the purpose of this article?
This article explains how to connect a Rheonics Sensor Module Electronics (SME) to ThingsBoard Community Edition over Modbus TCP, poll the sensor's Modbus registers using the ThingsBoard Gateway, and display live SRV/SRD data on a ThingsBoard dashboard.

TABLE OF CONTENTS

1. Overview

ThingsBoard is an open-source IoT platform for device connectivity, data collection, processing, and visualization. It can communicate with industrial devices over protocols such as Modbus TCP, which makes it a convenient platform for monitoring Rheonics sensors.


In this article, ThingsBoard Community Edition is configured to acquire data from Rheonics sensors via Modbus TCP, using the ThingsBoard Gateway, and to display sensor parameters in a real‑time dashboard.


Figure 1: Architecture of the Rheonics SME and ThingsBoard integration.

Figure 1: Architecture of the Rheonics SME and ThingsBoard integration.

2. ThingsBoard Setup

1. Install ThingsBoard by following the official Installation options documentation. This article uses ThingsBoard Community Edition installed via Docker, as described in Installing ThingsBoard CE using Docker (Windows).


2. After installing ThingsBoard, open a browser and navigate to http://localhost:8080, then log in as a Tenant Administrator. The default credentials are listed in the Docker installation guide linked above.

Figure 2: ThingsBoard login page.
Figure 2: ThingsBoard login page.

3. Gateway configuration

3.1 Create a gateway device

1. In ThingsBoard, navigate to Gateways.

Figure 3: Gateways section.

Figure 3: Gateways section.

2. Select Add gateway.

Figure 4: Add Gateway.
Figure 4: Add Gateway.

3. Enter a name for the gateway, select Default for the device profile, then click Create.

Figure 5: Gateway information.
Figure 5: Gateway information.

4. Download the configuration file from the launch command window.

Figure 6: Gateway configuration file.
Figure 6: Gateway configuration file.

3.2 Start the ThingsBoard Gateway

1. In the folder that contains the docker-compose.yml file, open a terminal and run:

docker compose up


2. The gateway status should appear as active.

Figure 7: Gateway status.

Figure 7: Gateway status.
⚠ Important — port conflict: ThingsBoard Gateway uses MQTT port 1883 to communicate with the ThingsBoard server. Confirm this port is free on the host machine before starting the gateway, if it is already in use by another service, the gateway will fail to connect.

3.3 Configure the Modbus connector

1. Click on Connectors configuration.

Figure 8: Connectors configuration.

Figure 8: Connectors configuration.

2. Add a new connector.

Figure 9: New connector.

Figure 9: New connector.


3. Fill in the connector with the following information:

  • Type: Modbus
  • Name: e.g. SRV
  • Logging level: Info

Figure 10: Add connector configuration.

Figure 10: Add connector configuration.

4. Disable remote logging.

Figure 11: Logs configuration.

Figure 11: Logs configuration.

5. Under Master connections, add a slave.


Figure 12: Add slave.

Figure 12: Add slave.

6. Fill in the following information:

  • Host: IP address of the SME
  • Port: 502
  • Method: Socket (TCP framer)
  • Unit ID: 255
  • Device name: e.g. SRV_1
  • Device profile: default


Figure 13: Slave configuration.

7. Add a time series by clicking the pencil icon to read an input register.


Figure 14: Slave time series.

Figure 14: Slave time series.

8. For example, to read viscosity:

  • Key: name of the variable, e.g. viscosity
  • Type: 32float
  • Function code: 04 – Read Input Registers
  • Address: 136
Figure 15: Time series configuration.
Figure 15: Time series configuration.

9. Click Apply and repeat this step to add any additional parameters needed — see the register reference in Section 4 for common examples.

Figure 16: Time series configuration.

10. Click Save. The connector status should turn green.


Figure 17: Connector status.

11. Navigate to Devices.


Figure 18: Devices.

12. Two devices should now be visible: one for the ThingsBoard gateway itself, and one for the SRV.


Figure 19: Active devices.

Figure 19: Active devices.


13. Click on the slave device, then open the Latest telemetry tab to confirm the parameters configured are visualized.


Figure 20: Latest telemetry.

Figure 20: Latest telemetry.

4. Modbus register reference

The table below lists commonly monitored Rheonics parameters and the corresponding Modbus input registers.


Table 1: Common Rheonics input registers

ParameterProtocol addressRegisterCountDescription
Parameter 12 – Viscosity Last Good1363001372 (Float32)Parameter 12 value as float.
Parameter 13 – Density Last Good1443001452 (Float32)Parameter 13 value as float.
Parameter 2 – Temperature Median563000572 (Float32)Parameter 2 value as float.
→ Check Modbus Input Registers for the complete list of registers available on Rheonics sensors.

5. ThingsBoard dashboard

To simplify deployment, preconfigured dashboard templates are available for SRV and SRD sensors.


1. Navigate to the Dashboards section and click the + button.


Figure 21: Dashboards.

2. Click Import file and select the dashboard file attached in this article for the sensor (SRD or SRV).


Figure 22: Dashboard files.

Figure 22: Dashboard files.

3. Add the attached images to your ThingsBoard Image gallery to make them available for use in the dashboard. See Image Gallery for instructions on uploading and managing images.


4. Open the imported dashboard.


Figure 23: Rheonics dashboard.

Figure 23: Rheonics dashboard.

5. Enter edit mode and edit each widget.

Figure 24: Widget configuration.

6. For each widget, select the configured device and the corresponding data key.


Figure 25: Updating device and data key.

Figure 25: Updating device and data key.

7. Repeat this process for the remaining widgets, then save the dashboard.

6. References