Wireless Modbus Applications

Wireless Modbus Applications

In modern building management systems, integrating wireless communication with existing wired devices such as controllers, thermostats, and sensors can significantly enhance system connectivity. This is particularly relevant for devices using Modbus RTU or BACnet MS/TP (Master-Slave/Token Passing) communication protocols. Wireless solutions simplify retrofitting and repairs by eliminating the need for complex wiring.

Key Wireless Modbus Applications


Example Application: Mitsubishi MelcoBEMS MINI

One practical application of wireless Modbus is with the Mitsubishi MelcoBEMS MINI ( PAC-UKPRC001-CN-1 ) and MelcoREMOTE. This setup allows for efficient monitoring and control of M-Series and P-Series units through the MelcoREMOTE device using Mitsubishi’s MelcoREMOTE phone application.

Connection Steps:

1. Control of Heat Pumps and AC Systems: The M-Series and P-Series units enable M-NET control for heat pump and air conditioning systems.
2. Protocol Conversion: The MelcoBEMS MINI connects to these units via the CN105 port, converting Mitsubishi’s M-NET protocol to Modbus or BACnet for compatibility with management systems that do not support M-NET. [Learn more about protocol converters here].
3. Wireless Connectivity: MelcoBEMS MINI connects to MelcoREMOTE using Modbus.
4. Remote Access: MelcoREMOTE features Ethernet connectivity for remote server or cloud platform access, allowing for remote control via the MelcoREMOTE app.


Visual Connections




wiring overview between indoor unit, MelcoBEMS, and MelcoREMOTE
Connection overview for MelcoBEMs and MelcoREMOTE


RS-485 connection between MelcoBEMS and MelcoREMOTE

RS-485 Connection between MelcoBEMS and MelcoREMOTE

 

Wireless Modbus and BACnet Solutions


Consider utilizing Lumenradio’s W-Modbus (W-Modbus) for wireless connectivity between the MelcoBEMS MINI and MelcoREMOTE. This device allows for seamless communication of Modbus signals, even in cases where existing wiring is compromised (or BACnet protocols for BACnet MS/TP).

 

W-Modbus application in wireless modbus connection between MelcoREMOTE and MelcoBEMS



Info
Complementary to the W-Modbus is the wireless BACnet ( W-BACnet ) device that can convert a wired BACnet MS/TP to a wireless BACnet network. Because the Mitsubishi MelcoBEMS also supports BACnet protocol, you can use the W-BACnet gateway/node to connect the M-Series or P-Series systems to a BACnet MS/TP network.

​Additional Applications


Wireless Modbus and BACnet devices can also be effectively used in various building management systems, including:

- Fan Coil Systems
- Heat Pump Systems
- Network Controllers and System Controllers

Example: Prolon Devices

For instance, you can interface the W-Modbus with the PL-VC2000 controller in a VAV box/terminal and T1000 room sensor as illustrated below.

 

wired connection between VAV controller and sensor

Wired connection between VAV controller and sensor

 

W-modbus devices connecttion between VAV controller and sensor

Wirelessly interfacing VAV controller and sensor with W-Modbus adapter

        

Alternative Solutions


Another option is Prolon’s PL-TREE-COM, a wireless Modbus adapter compatible with most Prolon controllers. Here are some sample applications:

1. Between VAV controller and a room sensor

PL-TREE-COM wireless communication between Prolon controller and sensor
PL-TREE-COM wireless communication between Prolon controller and sensor


2. Between a Master controller and follower controllers e.g between a rooftop controller (Prolon’s PL-M2000) and VAV systems for rooftop unit serving multiple zones.

 

PL-TREE-COM wireless communication between Prolon rooftop controller and VAV controller
PL-TREE-COM wireless communication between Prolon rooftop controller and VAV controller

 

Other Wireless Modbus Solutions

​
Consider Novus’s AirGate-Modbus, which is suitable for creating a network of wireless sensors by converting Modbus protocol to 802.15.4 protocol, utilizing ISM2.4GHz for wireless communication. 
 
AirGate-Modbus

Has long range and possible to connect an external antenna for improved wireless links. For configuration, use DigiConfig software which is a free.

For custom HVAC control solutions, feel free to contact  our HVAC Control Engineering team for assistance or learn more on our HVAC Controls website.


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