Modbus

In the Pierre Partner app, the Modbus section allows for the integration of Modbus devices with the Pierre system via a Modbus gateway. This setup is essential for controlling various HVAC systems and sensors through the Pierre smart home ecosystem.

Key Features:

1. Creating the Modbus Gateway:
A Modbus gateway is created to link Pierre with Modbus-compatible devices. During this setup, you define which pins are used for communication:

• TX Pin: Should be assigned to Configurable Pin 7 or 8.
• RX Pin: Can be assigned to any pin between 1 and 6.
  In this section, you can also configure important Modbus parameters such as Baud rate, parity, and stop bits.

2. Adding Modbus Devices:
Once the gateway is established, you can start adding Modbus devices. Each device must be:

• Addressed: Each device needs a unique address for communication.
• Named: Properly name the devices for easier identification within the system.

3. Device Control:
Through the Modbus integration, you can control a variety of devices such as:

• Heat pumps.
• VRF/VRV systems.
• Humidity and temperature sensors.
• Soil moisture measurement systems.
• Recuperators.
• Split or multi-split air conditioning systems.

This integration allows for enhanced control over complex HVAC and environmental management systems, ensuring that the Pierre system can fully automate and monitor these devices.

Pierre MODBUS Communication
The Modbus system is frequently used in building automation and industrial automation systems because it can be easily integrated with devices from various manufacturers and has wide support for different HVAC systems.

The Pierre system can communicate over Modbus, either directly or with a converter. We can apply this in two ways.

• Modbus TCP (Transmission Control Protocol) is a widely used communication protocol that enables device communication over a TCP/IP network, such as the internet or a local Ethernet network. Modbus TCP follows a client-server model, where devices on the network can act as clients or servers. A Modbus TCP client initiates requests, and a Modbus TCP server responds to these requests. This communication model allows for the control and monitoring of industrial devices. Using the Modbus TCP protocol, multiple master and slave devices can exist on the network.
• Modbus RTU (Remote Terminal Unit) is a communication protocol commonly used in industrial automation. It is part of the Modbus protocol family and is specifically designed for serial communication over RS-232 or RS-485 interfaces. The Pierre system uses the RS-485 interface. While Modbus TCP operates over Ethernet, Modbus RTU is typically used in situations where a wired serial connection is beneficial or necessary. With the RTU Modbus protocol, only one master device can be on the network.

Basic RTU Communication Requirements:

• Device Address (Slave ID): Each device must have a unique address.
• Baud Rate: Communication speed, typically 4800, 9600, or 19200 Kbps. Higher speeds reduce the maximum distance for communication but increase data transfer rate.
• Parity: Error correction, with one or two parity bits.
• Data Format: (8-bit format with 1 start bit, 1 or 2 stop bits, etc.). The start and stop bits are used to configure the MODBUS data packet. These settings must match across all network devices.

The same baud rate, parity, and data format are required for all devices using Modbus RTU to communicate with the Pierre system.

Examples of Using Modbus with the Pierre System:

• Master RTU: A Modbus thermometer connected to a Pierre display collects data, which can be retrieved remotely as a TCP master.
• Slave RTU: Devices controlled over Modbus - each device requires a unique address.
• Master RTU: The Pierre system communicates with various devices (fan coils, thermostats) and can send data via TCP.
  A temperature sensor connected to Pierre displays over Modbus RTU allows data from each display to be queried via Modbus TCP. If the Pierre display has a built-in temperature sensor, it can use Modbus RTU to control fan coils or thermostats. Only devices with matching specifications (baud rate, parity, etc.) can connect on Modbus RTU, while Modbus TCP enables communication with numerous devices over the network.

Another practical application is tracking energy consumption remotely for a house or apartment building. A Modbus thermometer connects to a Pierre display via Modbus RTU, while an Intesis box M-Bus to TCP converter is connected via Modbus TCP. By connecting calorimeters through M-Bus, the Pierre display can provide data from the calorimeter, such as electricity, water, gas consumption, solar power generation, or hot water production from solar collectors.

Pierre M-BUS (Meter Bus) Communication
M-Bus (Meter-Bus) is a European standard (EN 13757-2 for physical and link layers, EN 13757-3 for the application layer) for remote reading of water, gas, or electricity meters. It can also be used for other types of consumption meters, such as heating systems or water meters. The M-Bus interface is designed for communication over two wires, making it cost-effective. A wireless variant, M-Bus Wireless, is specified in EN 13757-4.

Required Equipment between the Pierre System and M-BUS Devices:

• Intesis M-Bus to Modbus Gateway
• Pierre Displays

Pierre displays (Rio, Helsinki, Berlin) each have an RS-485 connector, allowing direct communication with connected Modbus devices. They also have an RJ45 Ethernet port for internet access and are powered directly from the electrical grid (230V and neutral).

Modbus Integration into the Pierre System
Heating, cooling, and ventilation systems can be integrated into the Pierre system, typically via Modbus RTU.

For HVAC systems (Heating, Ventilation, and Air Conditioning), the following functions are available:

• Air Conditioning Units: Turn on/off, adjust temperature, control fan speed, and switch between heating and cooling modes.
• Fan-Coil Units: Turn on/off, adjust temperature, control fan speed, and switch between heating and cooling modes.
• VRV/VRF systems: Turn on/off, adjust temperature, control fan speed, and switch between heating and cooling modes.
• Ventilation and Air Handling Systems: Turn on/off and control fan speed.

Detailed procedure of Modbus integration in Pierre system
The following informations are needed from the distributor of the HVAC system:

• The distributor must check whether the desired HVAC system has the ability to communicate with Modbus.
• The distributor must provide information about the manufacturer, model number, technical specifications, and Modbus register table.
• The distributor must provide an appropriate Modbus gateway for the intended system.
• The Modbus gateway must be configured to operate with the intended system and provide a Modbus Address Table.

Integration requirements:

• HVAC systems are generally equipped with a wall thermostat. This must always be installed and connected to the system, as it is through these devices that the external units receive important information.
• The HVAC units must be commissioned beforehand. The system must function flawlessly before starting the Modbus integration.
• Power and internet must be provided on-site.
• The integration must be scheduled 15-30 days in advance.

Tasks on the Pierre side to be completed:

• Pierre's development team will begin the Modbus integration once they have received all the aforementioned information from the distributor and have ensured that the system on-site is operational, with power and internet available.
• Once the development is complete, internal testing ensures that the Pierre application sends the Modbus commands specified in the Modbus register tables provided by the distributor.
• With the partner's involvement, it must be verified on-site that the system operates without Pierre, using the wall thermostat or remote control. If everything is functioning properly, the Modbus commands are tested with a direct connection. This is where the accuracy of the provided Modbus registers can be fully confirmed. If everything works flawlessly at this stage, the system can then be connected to and tested with the Pierre system.