Unipi Neuron S103 (Raspberry Pi 4) is a programmable logic controller designed for automation, control, regulation and monitoring. The S103 (Raspberry Pi 4)’s universal architecture includes digital and analog I/Os, making it suitable for simple installations. The controller also features a single RS485 serial interface and a 1-Wire interface for connecting digital humidity or temperature sensors. The default Neuron S103 variant based on Raspberry Pi 3 Model B is available on this link.
Note: The product is not compatible with the Mervis system.
Unipi Neuron S103 (Raspberry Pi 4) is a programmable logic controller designed for automation, control, regulation and monitoring. The S103 (Raspberry Pi 4)’s universal architecture includes digital and analog I/Os, making it suitable for simple installations. The controller also features a single RS485 serial interface and a 1-Wire interface for connecting digital humidity or temperature sensors. The default Neuron S103 variant based on Raspberry Pi 3 Model B is available on this link. This product does not currently support the platform Mervis.
Raspberry Pi 4 Model B computer
|RS485 serial interface||1|
Digital inputs (DI) are designed to read binary logic states represented by direct voltage levels. That makes them suitable for reading data from various binary sensors and devices such as switches (on/off), motion sensors (movement detected/not detected), liquid level sensors (full tank/empty tank) etc.
Digital outputs (DI) are intended for switching various binary devices (lighting, smart door locks, drives of shutters and blinds etc.) through direct voltage. DO's also feature a Pulse-Width Modulation (PWM) function allowing to use the output for analogue control.
Analog input (AI) is designed to measure voltage, current or resistance to read values from various analogue sensors such as thermometers, pressure meters, tensometers etc.
Analog output (AO) serves for control of multi-state external devices through direct voltage or current and is suitable for control and regulation of devices such as three-way valves, heat exchangers, electric motors etc.
As a computing module, the controller uses an integrated Raspberry Pi 4 Model B computer featuring quad-core 1.5GHz CPU and RAM memory with selectable capacity (2, 4 or 8 GB). That gives them more than enough performance for various performance-demanding applications. MicroSD memory cards are used as memory storage.
Neuron controllers are by default provided with RS485 serial lines. This type of interface usually uses the Modbus RTU protocol and can be used to communicate with various devices such as Extension xS extension modules, energy meters, touchscreen HMI displays, controllers from other vendors, various sensors etc. A single bus can support dozens of devices while the bus' length can reach up to several hundred meters.
A single 1-Wire bus is also included. This interface uses 2-3 conductors for collecting data from various 1-Wire sensors such as thermometers, humidity meters, light intensity sensors etc.). A single 1-Wire bus supports up to 15 devices, the overall length of the bus can reach up to 100 meters.
All Neuron models also feature a single Ethernet port for network communication. The S103 (Raspberry Pi 4) model is equipped with a 1Gbit Ethernet port.
Thanks to the software openness of Unipi controllers customers can choose from a broad range of software solutions and are not limited to a single platform. Among supported solutions are both commercial and open-source systems. Visit the Guide for choosing the right software for the list of other supported solutions.
The main supported solution is the Mervis control system - a platform developed in accordance with the IEC 61131-3 standard for PLC programming, that includes SCADA interface for remote management and monitoring, a comprehensible development environment, a human-machine interface (HMI) editor and an online/on-premise database for storing historical data and retrospective analysis of the controlled technology's operation.
Aside from commercial platforms you can also choose any from the list of supported open-source solutions, or use the EVOK API (Websocket, REST,...) Modbus TCP, SysFS or other tools for implementing your own logic in any programming language. Visit this link for the list of supported software solutions.
All components of the controller are encased within a durable aluminium chassis (IP20 protection). On S103 (Raspberry Pi 4) the chassis also serves as a heatsink for the computing module. The controller is designed for mounting on a standard DIN rail (35 mm).
|Type S, size on a DIN rail = 4 modules = 7 cm|
|S103 (Raspberry Pi 4)||4||4||-||1||1||1||Raspberry Pi 4 Model B
(quad-core 1.5 GHz CPU)
selectable RAM capacity (2/4/8 GB)
2× USB 2.0, 2× USB 3.0
1× 1Gbit Ethernet
(2× micro HDMI port)
Aluminium chassis (IP20, heatsink)
|S103||4||4||-||1||1||1||Raspberry Pi 3 Model B
(quad-core 1.2 GHz CPU)
1 GB RAM
4× USB 2.0
1× 10/100Mbit Ethernet
Aluminium chassis (IP20)
|Type M, size on a DIN rail = 8 modules = 14 cm|
|Type L, size on a DIN rail = 12 modules = 21 cm|
1) GSM/GPRS module
2) IQRF wireless network coordinator (learn more)
Technical and safety information
Modbus register map
Table overview of Modbus registers
Declaration of conformity
Datasheet of the product
|CPU||Quad-core (1.5 GHz)|
|RAM||Selectable capacity (2 GB, 4 GB, 8 GB)|
|1-Wire bus||Yes (galvanically isolated)|
|Power||24 V DC¨|
|Mounting||DIN rail (35 mm)|
|Dimensions||70 mm × 90 mm × 60 mm|
|RTC backup||Max. 7 days|