Baxi Boilers

Baxi Andon terminal, showing 3D printed enclosure

Andon System

Baxi Boilers approached Tritec to develop a new ‘Andon’ system for a production line at their plant near Chorley. The system features custom hardware and software developed by Tritec, plus a custom designed 3D printed enclosure.

Andon is a manufacturing term originally from Japan, meaning a system to notify management of a quality or process problem.

The system features a number of user terminals, one at each station on the production line. Each terminal is equipped with an RFID card reader, two control buttons and numeric display. A central PLC monitors all the terminals and interfaces into Baxi’s in-house production control system.

Hardware and Embedded Software

Tritec developed a custom PCB for the project, featuring a Microchip PIC24 processor, Modbus communications interface and LED display. An MFRC522 device was used for reading the RFID cards.

Embedded software included low-level drivers for all the hardware features, control logic for operating the terminal and Modbus slave registers implementation for communicating with the PLC.


Tritec developed the software for the central PLC, from the small and compact Mitsubishi FX series.

At one side the PLC acts as a Modbus master, using Modbus RTU over an RS485 link to communicate with multiple terminals. On the other side there is SCADA Ethernet link which feeds information into Baxi’s production control system, providing real-time visualisation and logging of performance.

Mechanical design and 3D printed enclosure

Enclosures were designed from scratch to be robust and practical, ready for use in a busy production environment. Designing the enclosure in-house meant the RFID reader could be placed very close to the card, giving improved reliability in use.

As this was a relatively low volume product, the enclosures were 3D printed at Tritec using the thermoplastic Polylactic Acid (PLA). This avoided expensive tooling costs and enabled faster production.


The final units were manufactured and tested in house before being shipped to Baxi for installation.


Tritec-designed PCB for the terminals
Designing the 3D model in Creo Parametric
Completed 3D model prior to printing
3D printed cases - tops
3D printed cases - bottoms
Completed and functional unit undergoing test
Baxi production line showing installed terminals
Production line showing the installed terminals
Baxi production line showing installed terminals