GWU-5 + GridBit OS + GridBit Cloud. The IoT device management platform
GWU-5 connects the devices of a remote site to your systems. GridBit Cloud keeps every unit reachable, updated and secured, and it is built for the requirements of NIS2 and the Cyber Resilience Act. Your team writes the application, not the infrastructure.
Fleet firmware updates
New firmware goes to many gateways at once. If a version fails on a unit, that unit returns to the previous one.
Cyber security
The private key is created in the device and never leaves it. Secure Boot checks the kernel at every power-up, applications run in an isolated environment, and every action stays in an audit log.
Remote device management
Remote access to each deployed gateway: its parameters, its processes and the Modbus devices behind it.
Solutions
Each system combines GridBit hardware with the platform. Take a finished system, or develop your own on the gateway.
GridBit Cloud
Cloud management for fleets of industrial gateways: self-activation, over-the-air updates, alarms and remote access, with no access to your production data.
Street lighting
Control and monitor street lighting cabinets from one system, with schedules that follow sunrise and sunset, measurements per phase and alarms for every cabinet.
EIM
Sensors, analysers and a gateway turn a secondary substation into a monitored asset. The platform shows the transformer and the low-voltage board in real time, with alarms and reports for the grid operator.
OccuSense
Energy control for hotels by the real occupancy of the rooms. Presence sensors without cameras, automation of the room climate, and evidence for the EPBD requirements in one platform.
Benefits
Trips to the site, updates by hand and servers of your own all cost money. This is where GridBit Cloud saves it.
Configuration, diagnostics and firmware updates reach the device remotely. A technician goes out when the job needs hands.
A new version reaches the fleet in stages, at night if you want, and returns by itself where it fails.
Alarms by e-mail, Slack or Teams show a device that went silent or out of range.
GridBit Cloud is a managed service. Your production data goes straight to your systems, so nobody charges you by data volume.
GridBit keeps the devices reachable, configured and updated. Your team develops the logic your project needs.
Updates, a fleet inventory and an audit trail for what NIS2 and the Cyber Resilience Act ask about field devices.
In the field
The team behind GridBit has designed, installed and maintained metering and control systems since 2006. The numbers are those of ADD Bulgaria, the company GridBit comes from.
Bulgaria
Every night GridBit switches and measures the street lighting of 70 municipalities, from Sofia to the Black Sea coast. Remote metering with the electricity distribution companies started here in 2006.
North Macedonia
In 2011 smart metering crossed the border. Together with Bulgaria, the meters and the concentrators run in the grids of four electricity distribution companies.
Greece
Marina Flisvos in Athens, the largest private marina in Greece, meters its water and electricity with the first generation of GridBit hardware. It still runs today.
One team
The same engineers design the hardware, write the software and answer when something in the field fails. That is how systems stay in service for years.
Municipalities that run their street lighting on GridBit
Numbers of ADD Bulgaria and GridBit, 2026.
See the street lighting mapHardware
Gateways, a three-phase meter, an astronomical relay, a voltage detector and watchdog relays. Every module has a datasheet and a Modbus register map.
All hardware
GatewayGWU-54G LTE gateway for Modbus devices, with Ethernet and MQTT
GatewayGWU-42G/4G gateway for Modbus RTU devices, two digital inputs
GatewayGWU-22G GSM/GPRS gateway for Modbus RTU devices
MeterMCU-4Three-phase network analyser with Modbus RTU
RelayRTU-4Astronomical relay with Modbus RTU and energy saving mode
InputsSMU-3Eight-channel AC voltage detector with Modbus RTU
WatchdogWDT-1Watchdog relay that restarts devices when Modbus communication stops
WatchdogWDT-4Modbus watchdog relay, fallback to photo sensor or clockAbout GridBit
GridBit is a spin-off of ADD Bulgaria. The team has designed, installed and run monitoring and control systems on real grids, real streets and real buildings. The products on this site come out of that work.
AboutGridBit develops industrial IoT systems for energy, cities and buildings. The range covers the GWU-5 gateway with its operating system GridBit OS and seven more DIN-rail Modbus modules, the GridBit Cloud device management platform, and three finished systems: street lighting management, electrical infrastructure monitoring (EIM) and OccuSense energy control for hotels. GridBit is a spin-off of ADD Bulgaria from Plovdiv.
GWU-5 is a DIN-rail gateway that connects the devices of a remote site to your systems. It reads Modbus RTU devices on an RS485 bus and Modbus TCP devices on its LAN port, and sends the data over 4G LTE Cat 1, 2G or Ethernet. It also has Wi-Fi and Bluetooth. It runs GridBit OS, has one digital input, runs on 9 to 24 VDC and works from -20 to 60 °C. GridBit Cloud manages it remotely.
GridBit Cloud is the cloud platform that manages fleets of GWU-5 gateways. It covers self-activation with a QR code, remote configuration, staged firmware updates with automatic stop and rollback, alarms and remote access. The gateway sends production data straight to your broker, cloud or SCADA, so that data never passes through the platform.
GridBit OS is the operating system of the GridBit gateway. Your applications run on it in an isolated environment, it checks the signature of every package and of the kernel, and GridBit Cloud updates it over the air.
Yes. The gateway sends the data straight to your broker, cloud or SCADA, and you write the logic your project needs. GridBit Cloud keeps the devices reachable, configured and updated, so your team does not have to develop device management.
Electricity distribution companies, municipalities, ESCO and maintenance companies, and hotels. The hardware works in street lighting cabinets, transformer stations, pump stations and other remote sites, and OccuSense works in hotel rooms and plant rooms.
Send the form on the Contact page or write to office@add-bg.com. Say how many sites you have, which devices and which network. GridBit answers by email with a proposal for the gateway, the platform and the modules your project needs.
We answer with a proposal for the gateway, the platform and the modules your project needs.
Cookies and statistics
We use Google Analytics and Microsoft Clarity to see how visitors use this website and to improve it. Clarity records clicks, scrolling and mouse movement, never what you type into a form. With your consent both set cookies; marketing cookies also let Google add age, gender and interests. You can change your choice at any time under "Cookie settings" at the bottom of every page. Privacy policy