Unipi Neuron L533 is a programmable logic controller (PLC) designed for automation, control, regulation and monitoring. Aside from a high number of digital and relay I/Os the L533, as the highest model of the Neuron 500 line, offers the most analog I/Os from all Neuron models. The controller is equipped with three RS485 serial interfaces.
The L533 is a development successor of the Neuron L513.
Unipi Neuron L533 programmable logic controller is designed for automation, control, regulation and monitoring. The L533 is the largest model of the Neuron 500 line and aside of being focused onto a higher number of digital and relay I/Os it also features most analogue I/Os out of all Neuron models. Its wide functionality is then complemented with a pair of RS485 serial interfaces.
|RS485 serial interface||3|
*more detailed info about the number and type of analogue I/Os is available in the product's datasheet (see the Files tab above)
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.
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 inputs (AI) are designed to measure voltage, current or resistance in order to read values from various analog sensors (pressure meters, thermometers, tension gauges etc.).
Analog outputs (AO) are used to control and regulate devices such as three-way valves, electric motors, inverter drives, heat exchangers etc. by direct current or voltage.
The controller is powered by Raspberry Pi 3 Model B+ featuring quad-core 1.4 GHz CPU and 1GB RAM, or Raspberry Pi 4 Model B with quad-core 1.5 GHz and selectable RAM capacity (2, 4, or 8 GB). Giving it 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 200 meters.
All Neuron models also feature a single Ethernet port for network communication
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 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). The controller is designed for mounting on a standard DIN rail (35 mm).
|Type S, size on a DIN rail = 4 modules = 7 cm|
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
Aluminum chassis (IP20, heatsink)
Raspberry Pi 3 Model B+
(quad-core 1.4 GHz CPU)
1 GB RAM
4× USB 2.0
1× 300Mbps Ethernet
Aluminum chassis (IP20)
|Type M, size on a DIN rail = 8 modules = 14 cm|
|Type L, size on a DIN rail = 12 modules = 21 cm|
Modbus register map
Table overview of Modbus registers
Declaration of conformity
User guide and technical documentation
Quick instructions and safety information
Product features and technical information
Product line information
|CPU||RPi3: Quad-core (1.4 GHz)
RPi4: Quad-core (1.5 GHz)
|RAM||RPi3: 1 GB
RPi4: 2/4/8 GB
|USB||RPi3: 4× USB 2.0
RPi4: 2× USB 2.0, 2× USB 3.0
|1-Wire bus||Yes (galvanically isolated)|
|Mounting||DIN rail (35 mm)|
|RTC backup||max. 7 days|
|Dimensions||140 × 90 × 60 mm|