Node-HIU Control Panel

From Heatweb Wiki
Jump to: navigation, search

The node-HIU Control Panel is a pre-fabricated control system for use on heat networks and plant, providing a turn-key solution to monitoring and commissioning all the assets on a system.

The panel has been designed to interface with HIUs fitted in properties, a well as plant rooms running on commercial BMS systems, pulling all the available data together to a central point where it can be monitored and acted upon.


All customers want reliability, efficiency, and support when needed. So now we have put this into a box.

We call it the Node-HIU Control Panel, and its purpose is to fulfil our customers demands for reliability, efficiency, and support on heat networks, by keeping an eye on things, commissioning and tweaking control systems or HIUs, and connecting support with any problems identified.

The Node-HIU Panel is in essence a glorified router, taking data and routing it to where it needs to go.

It adds the ability to decide what data goes where, and when, as well as performing any calculations or analysis needed en route. At the same time, it acts as a communications hub and firewall, bridging internet networks, with local networks, and pulling in the various local control circuits such as HIUs, M-Bus meters, BMS systems, and Modbus devices.

Many customers have shown a strong desire for systems they can fully own, and which are contract free, so the panel delivers on that request. The panel is built using open-source technologies including Linux, OpenVPN, MQTT and Node-RED.

The use of MQTT and encryption, along with simple wiring logic, allows data to be regulated on site, with communications filtered and protected as needed, and sent on a need to know basis. MQTT allows two way communication, and is a standard for M2M communications and home control systems.

The panel it is delivered fully working, pre-commissioned, and communicating with the outside world, requiring only wall space and power to get started.

As manufacturer's of the most efficient HIUs ever independently tested (two years running), the Node-HIU Control Panel enables us to apply our ground-breaking technologies to all aspects of a network, and it is a guarantee that everything is working exactly as designed. In the same way the independent testing shows how an HIU performs in the lab, the Node-HIU panel puts the whole network on test in the real world.

Mission Objectives

The controls system enables one to:

  • Increase system efficiency by monitoring load and providing signals to plantroom equipment and HIUs
    • DP control of pumps
    • Boiler sequencing
    • Network supply temperature
    • Load shifting or shedding to reduce peak loads
  • Simplify the installation of systems by catching every snag as it appears
  • Detect problems with systems requiring human intervention
    • Low heating system pressure
    • Component failure or wear
    • Open bypasses
    • Blockages in pipes
  • Route alarms to the correct persons
  • Follow strict rules regarding data protection and transmission
    • No data storage unless a fault is detected
    • Data analysed at source, with defined alarm content sent to 3rd parties as programmed
    • Reduce traffic to alarms and messages only (for SIM limits as well as data protection)
  • Give users remote control over services
  • Option to run the whole lot contract free (other than internet provision) and without any ties to bespoke hardware or services
  • Ability to easily migrate new control logic from one system to another, and enable the collaborate evolution of heat networks.

See Also




  • Node-HIU RPi3 controller with touch screen monitor
  • Node-HIU RPi3 controller with 375GB hard disk storage
  • Node-HIU RPi3 controller with I/O
    • 2 x RS485 (Modbus or other protocols)
    • 0-24v analogue inputs
    • Cross over relay for fault circuit
    • Digital temperature sensors
    • 24v digital inputs/outputs
  • 5v and 24v power
  • GSM modem with twin SIM cards
  • Diversified protected aerials
  • 8 port managed Ethernet switch
  • Spare mains plug socket and USB power
  • DIN rail space for 3rd party metering equipment (e.g. M-Bus master)


  • 8 port managed Ethernet switch with PoE
  • 16 port managed Ethernet switch with Ethernet + Fibre
  • LoRaWAN radio network base station (up to 5km) (in development)
  • M-Bus Master


  • Full management of connected HIU network
  • GSM internet connection for commissioning and backup)
  • WiFi access point (for plantroom equipment and engineers)
  • MQTT server
  • Dynamic DNS (via NOIP)
  • Port forwarding
  • VPN server (x2)
  • Node-RED control system (x3)
  • Modbus master (RTU/TCP)
  • Commissioning dashboard (via LAN/VPN)
  • Heat network monitoring dashboard (via LAN/VPN/Display)
  • Fault diagnosis and reporting
  • Alarm routing to email, SMS, remote partner screens, or mobile push alerts

Control Software

  • Visual drag and drop programming environment
  • Javascript (Node.js) coding
  • Open-source

The software used to program the Node-HIU panel is Node-RED, an open source system driven by IBM. The platform allows one to easily program in logic by wiring together components, requiring no prior coding skills, and is similar to both the programming languages taught in schools, and those used on graphical PLCs. It also allows one to dive into a full coding environment based on JavaScript - possibly the most common software language there is.

Logic components or full systems can be easily copied and pasted, enabling collaborative development of standardised control functions. 3rd parties are able to develop their own components, with 'nodes' available to interact with a growing number of systems and online services.

Analysis Software

The following is a sample loading profile over 24 hours for hot water load on a network, taken from real world systems. The data is one second resolution, and enables the very brief (<10s) peak loads to be analysed.

Similar data on any system variables can be logged and analysed.



  • All communication made through MQTT
  • No ports open to the internet other than for MQTT and VPN
  • Traffic on a network to be restricted to known routes
  • Each service on each controller given random passwords

MQTT is a robust and extremely versatile protocol, used by many internet services, and can be opened up to the internet. The same is true of OpenVPN, the open-source standard package for providing secure remote network connections. No other incoming ports are required for operation of the system.

The Liberatum GSM Modem provided with the panel provides all firewall services, and enables port forwarding for MQTT and OpenVPN. Communications can be locked down to the known devices preventing access from unknown devices plugged into the network without authorisation.

Commissioning dashboards are only available within the local network, or over VPN connection.

Screen Examples


Remote DP & Temperature SensorPlantroom control systemM-BusData optionsHIU readings

Function Example 1: DP Control of Pumps

All plant-rooms need to be able to control the speed (power) of their main circulating pumps to match demand.


  • DP sensors on local heat network via Modbus RTU
  • DP sensors on remote heat network via MQTT
  • DP sensors in plant-room via 0-10v analogue
  • DP signals from HIUs running hot water outlets via MQTT/Modbus


  • Pump speed via Modbus RTU
  • Alarms via email


  • Minimum DP at an HIU
  • Minimum DP at a sensor on network


  • Run the pump to the minimum speed that keeps all minimum DP settings satisfied


Function Example 2: Load Balancing


  • Instantaneous HIU hot water loads
  • Network supply heat meter readings


  • Short term load request to HIUs
  • High resolution day-of-week load csv files
  • Alarms via email
  • Supply temperature valve control


  • Maximum network supply flow rate
  • Maximum/minimum network supply temperature
  • Maximum rate of change of network supply temperature


  • Meet short term peaks in demand by shutting down central heating temporarily (network wide hot water priority)
  • Match supply temperature to load patterns