Unipi Neuron L203 (RPi3)

Basic description

Unipi Neuron L203 is a programmable logic controller designed for automation, control, regulation and monitoring. The L203 features a high number of digital and relay I/Os complemented by a single analog I/O and an RS485 serial interface. With a total number of 70 I/Os, the L203 offers the highest number of inputs/outputs of all Neuron controllers. The controller is also provided with a 1-Wire interface for connection of digital temperature or humidity sensors.

Basic features

Digital inputs	36
Digital outputs	4
Relay outputs	28
Analog inputs	1
Analog outputs	1
RS485 serial interface	1
1-Wire bus	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 Ethernetm Wi-Fi, Bluetooth.
Raspberry Pi 3 Model B+ (quad-core 1.4 GHz CPU), 1 GB RAM, 4× USB 2.0, 1× 300Mbps Ethernet, Wi-Fi, Bluetooth.

Inputs & outputs description

Digital inputs (DI) are designed for reading states of two-state devices such as various digital sensors, switches and buttons, motion sensors etc. All digital inputs feature counter functionality by default. 

Digital outputs (DO) are applicable for switching two-state devices using direct current (DC) such as locks, external relays, contactors etc. DO’s can be also used for analog control thanks to the pulse-width modulation (PWM) function.

Relay outputs (RO) serve for switching devices with higher current draw and devices requiring alternating current (AC) such as water heaters, pumps, contactors or external relays with higher switching current.

Analog input (AI) is designed to measure voltage or current in order to read values from various analog sensors (pressure meters, tension gauges etc.).

Analog output (AO) is used to control and regulate devices such as three-way valves, electric motors, inverter drives, heat exchangers etc. by direct current or voltage.

Computing module

The controller is powered by Raspberry Pi 3 Model B+ featuring quad-core 1.4GHz CPU and 1GB RAM, giving it more than enough performance for various performance-demanding applications. MicroSD memory cards are used as system storage, which must be purchased separately.

Communication interfaces

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

Software options

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 Other software overview for the list of other supported solutions.

The main supported solution is the Mervis control system - a platform developed under 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 logic in any programming language. Visit this link for the list of supported software solutions. 

Package contents

• Neuron controller
• removable screw terminals
• DIN rail holder (35 mm)
• 3× DIN rail holder mounting screws
• 1× grounding screw
• instruction leaflet
• lifetime Mervis license code

Other features

All components of the controller are encased within a durable aluminium chassis (IP20 protection). The controller is designed for mounting on a standard DIN rail (35 mm). 

Neuron product line overview

Model	DI	DO	RO	AI	AO	RS485	Common features
Type S, size on a DIN rail =  4 modules = 7 cm
S103	4	4	-	1	1	1	Computing module: 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 Wi-Fi, Bluetooth Aluminum chassis (IP20, heatsink) or Raspberry Pi 3 Model B+ (quad-core 1.4 GHz CPU) 1 GB RAM 4× USB 2.0 1× 300Mbps Ethernet Wi-Fi, Bluetooth Aluminum chassis (IP20)
S103-G1	4	4	-	1	1	1
Type M, size on a DIN rail = 8 modules = 14 cm
M103	12	4	8	1	1	1
M203	20	4	14	1	1	1
M523	8	4	5	5	5	2
Type L, size on a DIN rail = 12 modules = 21 cm
L203	36	4	28	1	1	1
L523	24	4	19	5	5	2
L533	12	4	10	9	9	3

1) GPRS/GSM modem

Further info

• Neuron line introduction
• Comparison of Unipi product lines
• A guide for choosing the right software