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 Updated: 10 May 2020


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SonNet System
Standard system devices are used for the actual final installation, and consist of the receiver, battery powered ‘end devices’ (EDs) and, if required, permanently powered routers.

EDs achieve long battery life (5 years or more) by taking measurements only at predefined intervals and transmitting them to the receiver for processing.


At all other times an ED is in an ultra-low power mode. EDs can measure temperature and RH as well as offering momentary switch and setpoint knob facilities.




  Start guide Manual on request

Routers are ‘awake’ at all times to process data from EDs and respond to commands from the receiver. Routers can also have all the measurement features as an ED.

The receiver is the heart of the system and processes all data from EDs and routers for integration into a BMS or control system.


SonNet Parts

Battery Powered Sensors (EDs)
Sensor nodes are used in conjunction with the RF-RX20 or RF-RX40 receiver units, and if required (depending on installation topography), RF-RR series of routers.

Data is transmitted back to the receiver at configurable time intervals, or on a configurable change in measured value.

Each sensor retains these configurations if the battery becomes discharged or requires replacement. The sensors automatically find the best path back to the receiver, which may be directly to the receiver or via ‘parent’ routers.










Battery powered nodes are available in four formats

  • Space mounting temperature, with setpoint and momentary switch options

  • Space mounting RH&T, with setpoint and momentary switch options

  • Plant mounting temperature

  • Plant mounting RH&T

  • Why wireless? Market Requirements

  • Increased need to report / improve energy savings (Bldg Code)

  • High installed new installations cost with legcy wired system

  • Emerging refurbishment market (Over 70% of commercial space)


  • Enabling technologies emerging

  • New low power RF standards (IEEE 802.15.4)

  • Lower cost micro controllers with embedded radios

  • Maturing of battery technology PRODUCT POSITIONING BEST INSTALLED COST

  • Less wiring on install

  • Lower engineering cost

  • Little planning required prior to install

  • Simple commissioning

    The final system of devices permanently installed on site for the purposes of monitoring and control.

    Free software used to configure devices on the wireless network and to monitor the network topology.




    Technical Overview

    The Radio Network A SonNet radio system is comprised of a receiver, battery powered sensors and permanently powered routers. Routers, though permanently powered, can also have sensing elements, accomplishing both router and sensors functions.

    Routers and sensors can either communicate directly with the receiver or via other routers. Routers are required to be permanently powered as they need to stay “awake” at all times to allow signals from “child” nodes to be instantly forwarded to their “parent” nodes.

    Battery powered sensors only “wake” for very short periods to send data. In the schematic above, routers R2 to R7 have 5 children each, all battery powered sensors. Their parent is the receiver. Router R1 has 8 children and R8 has 4 children, giving a total number of network devices of 51, including the receiver. The receiver can support a maximum of 16 directly connected “child” devices, of which only 12 can be battery powered nodes, plus up to 4 routers. Routers can support a maximum of 16 directly connected “child” devices, of which only 8 can be battery powered nodes, plus up to 8 routers.

    There can be a maximum depth of 8 layers of routers in a network and a maximum of 50 nodes per network with the RF-RX series of receivers.

    Note that battery powered devices can only route their signals to the receiver directly or through routers, and not through other battery powered devices.

    How to use the SonNet Radio System

    1. Install Configuration and Monitoring Software (CMS)

    2. Connect the PC and switch on the receiver

    3. Start the CMS Software ... start the CMS application by clicking the icon

    4. Log on at administrator level

    5. Mount all routers, sensors and the receiver
      (in accordance with the plan made using the Site Survey Kit. Note the MAC address of each device)

    6. Power up all 24V routers and battery sensor nodes

    7. Authorisation of the devices

    8. View a list of all devices

    9. Turn off Auto Commision Mode

    10. Organise the devices in a graphical view

    11. See a summary of a device to map a sensor parameter to a receiver


    Radio Output:

    Frequency 2.4GHz, 16 channels, direct-sequence spread spectrum


    Compliance IEEE 802.15.4-2006

    Aerial Characteristics:

    Space: Gain 1.2dBi, VSWR 1.5:1

    Data Encryption:

    Plant: Gain 2.0dBi, VSWR 2:1

    Power Output:

    AES 128




    Temperature ±0.3°C Optional RH ±3% RH

    Battery Type:

    Space 3.6V AA 2.4Ah Li-SOCl2, non-rechargeable


    Plant 3.6V 2.1Ah 2/3 A Li-SOCl2, non-rechargeable

    Battery Life

    >3 years (depending on configuration)

    Plant Sensor Types:

    Duct, outside air, outside air with solar radiation shield, immersion, strap-on and flying lead


    E-mail: lars@fjellcom.se     

    Phone: +46(0)31-287202

    Mobile: +46(0)706-755561



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