Iono Pi

A PLC powered by Raspberry Pi

Iono Pi is a compact and flexible I/O controller that integrates analog and digital inputs, power relay outputs, and support for standard protocols such as 1-Wire and Wiegand, all built around the Raspberry Pi 3 or 4 quad-core processor.

It includes features essential for professional use, like a wide-range (9–28V) industrial-grade power supply delivering up to 4A at 5V, and a real-time clock backed by a lithium battery to ensure timekeeping even during power loss.

Thanks to the Raspberry Pi core, you can develop your applications using your preferred tools and frameworks, taking full advantage of the extensive open-source ecosystem.

Iono Pi is ideal for industrial automation, smart buildings, access control, and data logging applications, both in commercial and residential environments where durability, reliability, and regulatory compliance are critical.

It meets CE low voltage and EMC standards, conforms to harmonized safety and emissions directives, and is fully compliant with FCC and IC regulations as well as the RoHS directive.

Industrial-grade I/O controller with Raspberry Pi core

Mounting

• 4-module DIN rail enclosure
• Power and I/O terminals with screw connectors

Power Supply

• Operates from 9 to 28Vdc with built-in surge and reverse polarity protection
• 2.2A resettable fuse
• Supplies up to 4.0A on 5V rail (at 24Vdc input) to Raspberry Pi pins

Inputs and Outputs

• 4 power relays, each rated at 6A / 250V
• 2 analog inputs for 0–30V signals
• 2 internal analog inputs (0–3V) via onboard headers
• 7 configurable digital I/Os: dry contact input, voltage input, TTL-level I/O, or open collector output
• Native support for 1-Wire and Wiegand protocols

Reliability and Security

• Integrated real-time clock (RTC) with user-replaceable battery
• Embedded ATECC608A cryptographic chip for secure operations
• Optional SPBF10X active cooling fan with temperature control

Additional Features

• GPIO-accessible indicator LED
• Power status LED

Raspberry Pi Board

• Ethernet, 4x USB, HDMI (RPi 3) or dual micro-HDMI (RPi 4)
• microSD card slot
• Audio/composite video output
• WiFi and Bluetooth/BLE connectivity

Power Supply

The Iono Pi includes a robust and highly protected power regulation stage. It features large electrolytic capacitors, filtering inductors, protective diodes and a high-efficiency step-down converter. This setup can supply up to 4A at 5V and accepts input voltages from 9 to 28 Vdc. Designed for demanding environments, it efficiently handles ripple, electrical noise, and voltage fluctuations.

Relay Outputs

Equipped with four normally open power relays, Iono Pi handles loads up to 6A at 250V, with peak tolerance for inrush currents up to 15A. Each relay is controlled directly via GPIOs on the Raspberry Pi, making software control simple and flexible. These relays offer 5kV isolation (1.2/50 μs surge) between coil and contacts, and a mechanical life expectancy of over 5 million operations.

Analog Inputs

Two 0–30V analog inputs are accessible through the terminal block, using the Microchip MCP3204 12-bit A/D converter connected via SPI to the Raspberry Pi. Two additional 0–3V analog channels are available on internal headers for custom extensions. The converter offers fast sampling and high-resolution voltage measurements.

Digital Inputs

Six GPIO-linked pins can be used as digital inputs. Protected with resistor networks and Schottky diodes, they safely tolerate voltages up to 40Vdc. Three of them are shared with open collector outputs; the others can function as TTL-level I/O lines.

Open Collector Outputs

Three GPIO lines are connected to discrete open collector drivers, each rated for up to 100mA. These outputs include overcurrent and short-circuit protection. In case of fault, the output disables automatically and resets once the GPIO pin returns to low.

TTL I/Os, 1-Wire and Wiegand

Up to four I/O terminals support 0–5V bidirectional TTL signals through level shifters. These lines can be used for Wiegand readers, 1-Wire buses, or other digital communications.

Real Time Clock (RTC)

A battery-backed RTC module ensures continuous timekeeping, even during power outages. Based on the Microchip MCP79410 chip, it connects to the Raspberry Pi via I2C and provides advanced clock and calendar functions. The backup battery (CR1025) can last over 10 years under normal powered operation.