The Kappa4310Rasp is a Raspberry Pi-compatible Modbus RTU HAT designed to evaluate the IS4310 Modbus RTU Slave stack chip. This allows engineers to simulate sensor and actuator interactions using a push-button and RGB LED without requiring a custom board or soldering.
The board features an RS-485 interface with two RJ45 connectors for daisy-chaining Modbus networks. The board communicates with the Raspberry Pi over I²C and supports 500 Holding Registers along with Function Codes 3 (Read Holding Registers), 6 (Write Single Register), and 16 (Write Multiple Registers). The HAT operates at 3.3V and includes jumpers to enable or disable onboard I²C pull-ups. Additional features include dedicated Tx/Rx indicator LEDs, a power LED, GPIO-connected RGB LEDs, and a push-button for real-time interaction.
Kappa4310Rasp board specifications:
- Modbus RTU stack chip – IS4310 (I²C interface, 500 Holding Registers)
- Protocol support – Function Codes 0x03 (Read), 0x06 (Write Single), 0x10 (Write Multiple)
- Communication – RS485 via two RJ45 daisy-chained connectors
- Host interface – I²C (3.3V and 5V tolerant)
- Misc
- RGB LED on GPIO12, GPIO13, GPIO19 (PWM-capable, simulates actuator)
- Push-button on GPIO26 (simulates sensor)
- Power LED (Green)
- Rx LED (Yellow, blinks on incoming data)
- Tx LED (Yellow, blinks on Modbus response)
- Pull-up jumpers for SCL and SDA lines
- Power supply – Requires both 3.3V and 5V inputs
- Dimensions – Raspberry Pi HAT (compatible with Raspberry Pi and other SBCs)
Inacks provides a Python script on GitHub that demonstrates how to interface with the IS4310 chip over I²C using a Raspberry Pi. The example code includes reading a push-button input and writing it to the Holding Register 0, as well as controlling an RGB LED via PWM using values from Holding Registers 1, 2, and 3. INACKS also provides a Wiki where other resources, including documentation, hardware, software examples, and detailed information (datasheet) for the IS4310 chip are available.
Previously, we have seen devices like the Waveshare 8-channel RS485 to Ethernet industrial serial server, the Raspberry Pi CM4-powered CODESYS industrial controller, the Altech DO-1 Modbus monitor, and other devices that use the Modbus protocol for industrial applications. However, this is the first time we have come across a board based on the IS4310 chip.
The Kappa4310Rasp is available on Tindie for $15.00 and ships from Spain via Correos with tracking. Shipping to the US starts at $17.22 for the first item, with just $0.01 for each additional unit. You can select your country on the Tindie product page to see accurate shipping rates and availability for your region.
Debashis Das is a technical content writer and embedded engineer with over five years of experience in the industry. With expertise in Embedded C, PCB Design, and SEO optimization, he effectively blends difficult technical topics with clear communication
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[ the communication related settings are stored within a non-volatile flash (device id, baud rate, parity bit, stop bit), what’s re-writable for about 10k times, modbus registers are RAM (thx) ]
I COULDN’t understand some points,because ı’m new at the MODBUS or something like this.what can we use this device for and can you descirbe this device with basic words,becuse ı am from turkey,so ı don’t know english so well.
All that effort, then not isolating the rs485 link.
You cannot safely and sensibly run the logic 0V of your computer over hundreds of feet of cable.
Just finish the flipping job.