C4-digital+analog IOs+relays
  • C4-digital+analog IOs+relays
  • C4-digital+analog IOs+relays
  • C4-digital+analog IOs+relays

C4-digital+analog IOs+relays

® Compute Module 4

RESI started to use Raspberry Pi® products since Compute Module 3. RESI installed thousands of controllers in their own projects over the years. The result out of this experience is an industrial grade IoT controller build around the original Raspberry Pi® Compute Module 4 board.


First of all we put the Raspberry Pi® Compute Module 4 board into an industrial housing for DIN rail and wall mounting. We offer versions with 4MU, 8MU and 12MU size. Our C4 controllers fit perfectly into a standard switchboard cabinet with the 45mm cutout in the front panel used in almost every building automation environment. Walso installed a wide range power supply 12-48Vdc. Next we added an ARM® co-processor to handle the serial RS485 interface and all other time critical things. But this co-processor offers more: Unique 96-Bit serial number, integrated 2kB ferromagnetic RAM for persistent values, real time clock with backup capacitor, status LEDs and DIP switch for software use! Of course the standard features of the Raspberry Pi Compute Module 4 are available: 1xMicro HDMI, 1xEthernet, 2xUSB 2.0, 2/4/8GB RAM, 32GB SD-CARD with LINUX OS!


We build various different versions with integrated IOs: The ARM® co-processor handles all this IOs internally. So you have to use only a serial interface in your software to access all IO functions. Use dev/ttyACM0 to communicate with a simple ASCII text protocol or use dev/ttyACM1 to communicate with MODBUS/RTU master protocol.

Beside various types of digital inputs & outputs we offer versions with relay outputs. Also we have some special IOs in out portfolio: for LED stripes, for temperature sensor inputs, for shade&blind control.

The best part are our universal analog inputs or outputs (AIOX). We offer 4/8/16 channels. Every channel chn be individually configured to be:
Analog input for 0/2-10V or 0/4-20mA
Analog output for 0/2-10V or 0/4-20mA
Resistor measurment input of 0 to 1MOhm
PT100, PT1000, NI1000-DIN43760 sensor input
Digital input for 24Vdc or dry contact


This ARM® co-processor maps the RS485 interface via USB a serial interface /dev/ttyACM2.
This is a native serial interface in every LINUX software. The time critical direction switching for the RS485 is done by the co-processor, not by the LINUX!


We sell the IoT controllers with standard Raspberry Pi LINUX distribution. We intend to use this controllers with almost every available open source LINUX software like:
Node-RED; NodeJs, Phython, Java, JavaScript, HTML, C#, C++, Scratch, …
But you can also run all SQL and non SQL databases like
MariaDB, MongoDO, InfluxDB, PostgreSQL.
Use Grafana or Apache to build your UI.
For home automation use 
OpenHAB, FHEM, home assistant or IObroker.
Connect to cloud via 
MQTT, HTTPS, Azure IoT or AWS web services.
Create VPNs and Router with 
OpenWrt, OpenRouter, OpenVPN or WireGuard.
Use KODI for multimedia solutions.
CODESYS to realize industrial grade PLC solutions.

Or develop and distribute 
YOUR OWN SOFTWARE on a professional hardware platform!

Raspberry Pi is a trademark of the Raspberry Pi Foundation.
More information under www.raspberrypi.org



These are our flagship Compute Module 4 based IoT Controllers with integrated digital inputs, relay outputs and additional universal analog inputs and outputs. Our digital inputs are designed for 12-48Vdc signals. Our relay outputs are designed for max. 30Vdc, 250Vac and 6A per channel. We use as relay contact material only AgSnO2. Additional versions with solid state relays (1A, 230Vac/dc or 3A, 6Vac/dc or 6A, 6Vac/dc) offer unlimited switching cycles. This allows the complete control, monitoring and alarming of a remote station. In addition our universal analog inputs and outputs allow the configuration of a different analog IO function for every channel: Analog input (0/2-10V or 0/4-20mA) or analog output (0/2-10V or 0/4-20mA), resistor input (0-1MOhm), PT100, PT1000 or NI1000-DIN43760 temperature sensor input or digital input for dry contact or 24Vdc. Use this versions as a perfect IoT PLC or DDC. Sorry, but there is no space left for build-in 2nd Ethernet or LTE modem.

Select your version:
NOTE: Not all combinations are technical possible. Check product details for the order number of your selected controller


C4-universal analog IOs: 4xuniversal analog IOs
C4-digital IOs+relays: 32xDI+12xRO
C4 RAM Size: 2GB

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