The PIERRE Thermostat T2 is a room thermostat designed for temperature control and integration into the PIERRE Smart Home Solution.

The thermostat is available in black and white, with different versions depending on the required communication method and supply voltage.

The T2 can be integrated into the PIERRE system using:

• Modbus RTU communication – for PIERRE PRO installations,
• Zigbee communication – for PIERRE WAVE installations.

Depending on the selected version, the thermostat is available with:

• 24 V supply voltage, or
• 230 V AC supply voltage.

The T2 supports hybrid operation. It can perform local temperature control directly at the thermostat, while Modbus RTU or Zigbee communication allows it to be integrated into the PIERRE system for centralized control, monitoring, application access and Automations.

Available Versions

When selecting a PIERRE Thermostat T2, two main parameters must be considered.

Communication:

• Modbus RTU
• Zigbee

Supply voltage:

• 24 V
• 230 V AC – L, N

The selected thermostat version must always correspond to the communication method and supply voltage of the installation.

PIERRE WAVE – Zigbee Integration

Zigbee Communication

The Zigbee version of the T2 Thermostat is designed for integration into a PIERRE WAVE system.

The thermostat requires the appropriate 24 V or 230 V power supply, depending on the selected model, while communication with the PIERRE system is wireless via Zigbee.

The T2 Thermostat can be paired with:

• a PIERRE One Gateway, or
• a compatible PIERRE Display with integrated Zigbee Gateway functionality:
  • RIO 4”
  • HELSINKI 6”
  • BERLIN 10”

In this configuration, the PIERRE Display can operate both as a room control interface and as a Zigbee Gateway, providing communication between the T2 Thermostat and the PIERRE system.

WAVE System Principle

T2 Thermostat → Zigbee → PIERRE One Gateway / PIERRE Display → PIERRE System

No Modbus communication cable is required between the T2 Thermostat and the PIERRE system in this configuration.

Zigbee Network and Coverage

A stable Zigbee connection is required between the T2 Thermostat and the PIERRE One Gateway or a compatible PIERRE Display operating as a Zigbee Gateway.

The quality and range of wireless communication can be affected by:

• distance between the thermostat and the Gateway,
• thick concrete or reinforced concrete walls,
• multiple floors,
• building structures and other obstacles that attenuate radio signals.

Where the distance is significant or the building structure reduces Zigbee coverage, Zigbee repeaters can be used to extend and strengthen the network.

Depending on the size and layout of the project, additional PIERRE Zigbee Gateways can also be installed to provide appropriate coverage.

For larger buildings, multi-storey installations or buildings with significant reinforced concrete structures, Zigbee coverage should be considered during the system design and Gateway placement.

PIERRE PRO – Modbus RTU Integration

Modbus Communication

The Modbus version of the T2 Thermostat can be integrated into a PIERRE PRO system using wired Modbus RTU communication.

This configuration requires:

• a T2 Modbus Thermostat with the appropriate 24 V or 230 V supply voltage,
• a PIERRE PRO Controller,
• a TTL Converter Module,
• appropriate thermostat power supply,
• Modbus communication wiring.

The thermostats are connected to the communication network according to the applicable PIERRE Modbus wiring documentation.

24 V Version

For a 24 V Modbus T2 Thermostat, power supply and Modbus communication can be provided using a suitable 4-core cable:

• 2 conductors – 24 V power supply,
• 2 conductors – Modbus communication.

This allows both the thermostat power supply and Modbus communication to be provided through a single suitable cable.

230 V Version

The 230 V T2 Thermostat requires an appropriate L and N power supply.

Modbus communication wiring must be installed according to the applicable PIERRE wiring requirements.

Mains-voltage and communication wiring must be installed in accordance with the applicable electrical installation requirements and PIERRE documentation.

PRO System Principle

T2 Thermostat → Modbus RTU → TTL Converter → PIERRE PRO Controller → PIERRE System

Heating and Cooling Control

The T2 Thermostat can be used in different heating and cooling control architectures.

Depending on the system design, the heating or cooling valve actuator can be controlled either directly from the thermostat or centrally through the PIERRE PRO Controller.

1. Control from the Thermostat Relay

The T2 Thermostat's own relay output can be used to control a compatible heating or cooling circuit.

In this configuration, the thermostat performs the local temperature regulation and switches the connected compatible valve actuator or control input through its own output.

This allows the thermostat to continue performing its local temperature-control function independently while also being integrated into the PIERRE system through Modbus or Zigbee communication.

2. Control from the PIERRE PRO Controller

In a PIERRE PRO Modbus installation, the T2 Thermostat can provide room temperature and control data to the PIERRE PRO Controller through Modbus RTU.

The actual heating or cooling circuit can then be switched from the outputs of the PIERRE PRO Controller.

For example, with 230 V thermoelectric valve actuators, the control principle can be:

T2 Thermostat → Modbus RTU → PIERRE PRO Controller → Controller Output / Relay → 230 V Thermoelectric Valve Actuator

In this architecture, the T2 Thermostat provides the room temperature information and local user interface, while the PIERRE PRO Controller performs the centralized switching of the heating or cooling circuits.

This can be particularly useful where multiple heating and cooling zones are centrally wired to the distribution board.

Standalone and Integrated Operation

An important feature of the PIERRE Thermostat T2 is that it can operate both as a local thermostat and as part of the PIERRE system.

The user can control the room temperature locally from the thermostat.

When integrated through Modbus RTU or Zigbee, thermostat data and supported functions become available to the PIERRE system, allowing the local thermostat control to be combined with:

• centralized PIERRE control,
• application access,
• compatible PIERRE Displays,
• Scenes,
• schedules,
• Automations.

The exact functions available through the PIERRE system depend on the selected T2 version and system configuration.

PIERRE PRO vs. PIERRE WAVE

Technical Notes

• Always select the correct T2 version according to the required communication method and supply voltage.
• PIERRE PRO and PIERRE WAVE use different communication architectures: Modbus RTU for PRO and Zigbee for WAVE.
• A 24 V or 230 V T2 Thermostat must only be connected to its specified supply voltage.
• A PIERRE PRO installation with a Modbus T2 Thermostat requires a PIERRE PRO Controller, TTL Converter and appropriate Modbus communication wiring.
• A PIERRE WAVE installation requires a compatible PIERRE Zigbee Gateway, such as the PIERRE One Gateway or a compatible RIO, HELSINKI or BERLIN Display.
• In WAVE installations, the distance between Zigbee devices and Gateways, as well as walls and building structures, can affect wireless communication.
• Where Zigbee coverage is insufficient, Zigbee repeaters or additional appropriately positioned PIERRE Zigbee Gateways can be used to improve coverage.
• Zigbee network coverage should be considered during system design, particularly in large, multi-storey or reinforced-concrete buildings.
• Heating and cooling valve actuators can be controlled from the appropriate T2 Thermostat output or, in a PRO installation, from the appropriate PIERRE Controller output depending on the system architecture.
• Modbus wiring, device addressing and communication parameters must follow the applicable PIERRE Modbus documentation.
• All thermostat, Controller, valve actuator and communication wiring must follow the applicable PIERRE wiring documentation and electrical installation requirements.