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UniPi Axon L505


UniPi Axon L505 is a programmable logic controller (PLC) designed for control, monitoring and regulation. Being an enlarged variant of the Axon M505 model, the L505 combines a higher of analog I/Os with a high number of digital inputs and relay outputs. 


  • universal architecture with a very high number of I/Os
  • increased number of analog I/Os, four serial lines (RS485 + RS232)
  • durable aluminium chassis (IP20 protection), wider operating temperature range
  • integrated industrial computer (quad-core CPU, 1 GB RAM)
  • onboard 8GB eMMC memory
  • designed for DIN rail mounting
  • features RS485 serial line for Modbus communication
  • software openness (based on Linux OS)
  • preinstalled Mervis software (can be manually reflashed)

Power supply

718,99 € - 747,09 €
594,21 € - 617,43 € excl. TAX
More than 20 items in stock



The UniPi Axon L505 is an enlarged variant of the M505. Its architecture thus features multiple analogue I/O modules combined with an increased number of digital inputs and relay outputs. The communication interface configuration of the M505 was retained.

Multiple analogue inputs can be used for automation tasks requiring either receiving of voltage or current signal for gathering data from corresponding sensors (such as resistance thermometers), while analogue outputs are designed for control and regulation of external devices such as three-way valves or heat exchangers

Inputs & Outputs

24 digital inputs (DI) are designed for reading logical states (true or false), which are represented by levels of DC voltage. That makes them suitable for reading two-state sensors such as switches (on/off), movement sensors (movement/no movement), water level sensors (water present, no water) etc. The software detects logical 1 (true) if the input voltage between given DIx.y and DIGND is between 5-30V. If the voltage is lower than 3.5V, the state is evaluated as 0 (false)

4 digital outputs (DO) are used for controlling two-state devices such as lights, door locks, window blinds etc. Digital outputs on our controllers also feature the PWM (Pulse-width modulation) function, enabling a special type of analogue control. Outputs are of the NPN type (open collector) and can control devices with voltage up to 50V and up to 750mA load current.

19 relay outputs are used for control or switching of devices with higher current loads. ROs are thus suitable for controlling light bulbs, thermoelectric valve drives, water heaters, pumps etc. Relay outputs on UniPi controllers are rated for 5A max. current at 230V AC/30V DC voltage.

5 analogue inputs (AI): The controller features two types of analogue inputs. Group 1 analogue input (AI1.1) can be used either for voltage (0-10V) or current (0-20mA) measurements depending on AI register settings. Group 2 analogue inputs (AI/AIS2.1-AI/AIS2.4) feature four modes based on register settings. 

  • voltage measurement 0-10 V (16bit resolution)
  • voltage measurement 0-2.5 V (24bit resolution)
  • current measurement 0-20 mA (16bit resolution)
  • resistance measurement (from PT100, PT1000 or NTC sensors) using three-wire (three conductors, 0-100 Ω, 24bit resolution) or two-wire (two conductors, 0-1960 Ω, 24bit resolution) wiring method.

5 analogue outputs (AO): The controller features two types of analogue outputs. Group 1 output (AO1.1) can be used for 0-10V DC voltage, 0-20mA direct current or for resistance measurements (0-2kΩ, Ni1000 or Pt1000). Group 2 analogue outputs (AOV2.1-AOV2.4) feature 0-10V DC voltage only. 

I/Os of the Axon line have the same functionality as those on the Neuron line. Detailed info about I/O usage and settings can be found in the Neuron technical documentation

Communication interface

The unit features three RS485 serial lines. This type of serial line most often uses the Modbus RTU protocol. It can be used for communication with a wide variety of devices such as energy meters, touchscreen HMI panels, PLCs from other vendors or our Neuron xS extension modules. The bus can communicate with up to 32 devices with its total length being up to several hundred meters.  

The controller also features a single RS232 serial line for communication between two devices. In automation, it is most often used for communication with HMI displays, various gateways or closed technologies. 

Included is a single 1-Wire bususing 2 or 3 conductors for communication with simple sensors such as thermometers, humidity meters or light intensity meters. A single bus can communicate with up to 15 sensors with a maximum total length of the bus up to 100 meters. 

For network communication, a single 1Gbit Ethernet is provided.

Software options

Customers can choose from a wide variety of software solutions thanks to the open nature of Axon controllers and are not limited to a single platform. Available are both professional and open-source solutions.

Our main supported solution for UniPi controllers is the MervisThis platform is developed in accordance with IEC 61131-3 PLC programming standard and contaiíns SCADA interface for remote management and monitoring, comprehensible development environment, user interface (HMI) editor and online/on-premise database for data storage and retrospective operation analysis of monitored technologies. 

Aside from commercial platforms, several open-source solutions are available as well. Alternatively, customers can use their own code or implement Axons into already existing software solutions through the use of EVOK open-source API.

Visit this link for supported software overview. 

Other features

8GB eMMC onboard memory provides a high degree of reliability during repeated rewrites compared to systems using memory cards.

All components are protected by a durable anodized aluminium case providing IP20 protection. The unit’s size is 12 DIN modules, DIN rail holder is included in the package. 

Standard model overview

Product DI DO RO AI AO RS485 RS232 1-Wire Common features
Type S, size on DIN rail: 4 modules (7 cm)  
S105 4 4 - 1 1 2 1 1

Common features

Ethernet 1 Gbit

4x 1.2 GHz, 1GB RAM


Wi-Fi, Bluetooth

S115 4 4 - 1 1 4 - 1
S155* 4 4 - 1 1 2 1 1
S205 8 - 8 - - 1 - 1
S215 8 - 8 - - 1 1 -
S505 - - - 4 4 1 - 1
S515 - - - 4 4 1 1 -
S605** - - - - - 1 1 -
Type M, size on DIN rail: 8 modules (14 cm)
M205 20 4 14 1 1 2 1 1
M505 10 4 5 5 5 3 1 1
M515 6 - 5 8 8 2 1 -
Type L, size on DIN rail: 14 modules (21 cm)
L205 36 4 28 1 1 2 1 1
L505 24 4 19 5 5 3 1 1

*2x Ethernet (1 Gbit + 10/100 Mbit)
**4x IEC 62386 (DALI-compatible)

Further info


Declaration of conformity
Datasheet of the product
Instruction leaflet
Technical and safety information

CPU 4x 1.2 GHz
Internal memory 8GB eMMC
USB 2.0 2
Ethernet 1 Gbit
Analog inputs 5
Digital outputs 4
Digital inputs 24
Analog outputs 5
RS232 interface 1
RS485 interface 3
Power 24V DC
Relay outputs 19
1-Wire bus Yes (galvanically isolated)
Dimensions 210 mm x 90 mm x 60 mm
Weigth 1100 g
Mounting DIN (35 mm)
RTC backup max. 7 days

UniPi Axon S505

399,00 €
329,75 € excl. TAX

Less than 20 items in stock Show variants

UniPi Axon L205

619,00 €
511,57 € excl. TAX

Less than 20 items in stock Show variants