Off-Grid Systems website
Project duration: ~10 months
Projectvorm: Fixed price
Period: 2015-2016
Activities: Idea, proof of concept, design electronics, firmware & support software, prototyping, production, support & warranty
Technologies: STM32 Cortex M3 & M4, Ethernet, GPRS, CAN, C, USB, USB Host, FreeRTOS, FatFs, LwIP (TCP/IP, NetConn, PPP), HTML, JSON, AJAX, GPS, micro-SD, DipTrace, EmBits
Parts: STM32F407, STM32F417, MCP2562, LM3671, A8498, MMA8451, MAX9920, INA211, LM334, SIM28M, SIM800, LAN8720A


Development of a modular remote access & monitoring device for off-grid power systems. These systems are used for various outdoor applications that require a significant amount of electrical power. For example camera arrays at construction sites.

These systems employ various means of power generation and storage. Large capacity battery banks for (night-time) silent operation, these can be low cost lead-acid batteries or light weight lithium-ion packs. Power is generated from limited-power mains feed, tapped from road-side lighting, using a diesel generator, solar cells, or fuel-cell devices.

The customer needs a generic system controller which handles the network communication and some basic measurements and actions that apply to all system configurations. Interfacing with all the special power sources is handled using dedicated interface/option modules.

OGS Controller, I/O and motor driver


  • Operating voltage 7VDC-40VDC
  • Analog inputs for voltages (70V), current shunt and resistive sensors
  • 3 Digital/pulse/PWM opendrain outputs with diagnostics
  • Networking via ethernet or optional XBee®-style GPRS module
  • Supports HTTP, Telnet, FTP, uPnP, NetBios, SNTP, MQTT and raw TCP network services
  • Accelleration sensor for motion/shock detection
  • Internal I²C connection for limited internal expansion possibilities
  • CAN bus with proprietary OGS protocol to connect with system expansion modules
  • Data reporting triggered by various events; geofence, G-force (shock), inputs, periodic, etc
  • USB Host flashdisk support for firmware & configuration updates and easy dumping of logfiles
  • Italtronics multilevel Railbox DIN-rail mounted enclosure
  • Prepared for internal 20Wh Li+ backup battery
  • GPS


DIN-rail T-Bus

The OGS control® bus is a proprietary communications layer on top of standard 1Mbps 11-bit CAN. We have extended the standard CAN functionality with node identification, firmware update, file transfer, bus conflict detection and watchdog features. This bus is used to communicate with up to 127 option modules.

Option modules:

The system controller is complemented with a variety of expansion modules. Most of these modules are designed as DIN-rail mounted devices, just like the controller itself. They communicate via the T-bus power+communication distribution interconnect, which is mounted in the DIN rail channel.


In addition to a proprietary TCP socket-based communications channel, this system supports various standardised networking capabilities, such as HTML server with 'CGI' support, JSON, FTP server and Telnet access.

The default HTML view renders blocks for all connected devices and gives continuous updates of the variables using asynchronous JSON requests (AJAX):
HTML view of entire system

Agentschap NL
Gerealiseerd onder het
innovatieprogramma WBSO

ARM Cortex M3

'OGS control' is a registered trademark of Reijneveld Machinebouw B.V.
XBEE is a trademark of Digi International Inc.