Description

The IS4310-ISO485M6 is a Modbus ISOLATED RS485 module that integrates a Modbus RTU stack chip (IS4310), an RS485 transceiver and two daisy-chained RJ45 connectors. The module isolates the RS485 bus from the rest of the electronics, ensuring a robust solution for harsh electrical environments or long RS485 cable runs with significant ground potential differences.

By integrating this module into your project, you instantly get a working Modbus RS485 interface — just read from or write to the IS4310's I2C memory registers, which directly map to the Modbus Holding Registers.

This solution minimizes the design effort required to integrate a Modbus RTU Slave with an RS485 physical layer.

Optionally, you can integrate the IS4310 chip in your own design to minimize costs and customize the connector. Example schematics can be found in the IS4310 datasheet.

The IS4310 is a chip that integrates a Modbus RTU Slave stack. It features an internal memory of 500 Holding Registers, accessible by both a microcontroller (via I2C) and a Modbus Master device (e.g., PLC, computer, etc.).

You can use the IS4310 in three modes:

• As a Sensor → your microcontroller writes data to the chip via I2C.
• As an Actuator → your microcontroller reads data from the chip via I2C.
• Mixed → your microcontroller reads and writes data to the chip via I2C.

Just read/write the registers you need — no protocol stack required.

The goal of the IS4310 is to eliminate the engineering effort typically required to implement and validate Modbus RTU communication. It offers a reliable, ready-to-use solution that helps reduce development time and speed up your time-to-market (TTM).

Examples and Documentation

This Module (IS4310-ISO485M6)

• 📄 User Manual
• 🧩 Module Schematic

Modbus Chip (IS4310) used in this module

• 📄 Datasheet
• 📘 Online Wiki
• 📎 Product Flyer

Firmware Example Projects

• 👉 IS4310 Modbus Sensor for Arduino
• 👉 IS4310 Modbus Actuator for Arduino
• 👉 IS4310 Modbus Device for Nucleo-STM32
• 👉 IS4310 Modbus with Python for Raspberry Pi

Others

• Download Modbus RTU Master Software for Windows: qModMaster

How does the module work?

The module provides two interfaces:

• A castellated hole I2C interface for your microcontroller, FPGA, Arduino, Raspberry Pi, etc. This is where your system reads and writes Modbus data.

• An isolated RJ45 RS485 output, which serves as the fieldbus interface. It connects the module to the Modbus bus, allowing communication with slave devices and the Modbus master (a PLC, computer, or machine).

The internal memory is composed of 504 registers:

• 500 Holding Registers for user data.
• 4 Configuration Registers for communication settings: Modbus Slave ID, Baud Rate, Parity, Stop Bits.

The 500 Holding Registers are the key:

Whatever you write to the 500 Holding Registers via I2C will be accessible by the RS485 master device — and vice versa: whatever the RS485 master device writes to the 500 Holding Registers will be accessible by your microcontroller via I2C.

Default Module Settings

Default Modbus Settings:

• Modbus Slave ID: 1

• Modbus Baud Rate: 19200 bps

• Modbus Parity: Even

• Modbus Stop Bits: 1

Default I2C Settings:

• I2C Slave Address: 0x11 (fixed)

• I2C Speed: Depends on pin 7: 100 kHz (pin 7 to GND), 400 kHz (pin 7 to 3.3V/2), 1 MHz (pin 7 to 3.3V)

IS4310 Advantages and Features

Firmware Advantages

• 🛠️ Forget about Modbus RTU protocol handling: No need to deal with frame parsing, T1.5 and T3.5 timings, CRC or UART and Timer interrupts

• ❌ No libraries needed: Just use standard I2C functions

• 🧠 500 Holding Registers available for your use.

• ⚡ Perfect for heavily loaded CPUs or ISR-heavy microcontrollers

• 📝 Arduino, STM32, and Raspberry Pi examples available

• 🧪 Evaluation board available to make some tests in Arduino/Nucleo and Raspberry Pi form factor

• ⏱️ Save firmware engineering time

Hardware Advantages

• 🔌 Save pins on your microcontroller: No need to sacrifice any UART pins as it uses I2C, a shared interface

• 🧘 Reduce the CPU load of your microcontroller

• 💾 Reduce Flash and RAM memory footprint

• ⚙️ Save microcontroller resources (UART, Timers, etc.)

• 🗂️ Schematic design examples available for RS485, RS485-ISOLATED, RS232

Compatibility Advantages

• 🔄 Great for non-deterministic systems (like Raspberry Pi and single-board computers)

• 💡 Compatible with 5V I2C serial interfaces

• 🔋 Compatible with 5V RS485 transceivers

• 🏎️ Supports I2C speeds: 100kHz, 400kHz, and 1MHz

• 🖥️ Ideal for FPGA designs

Production Advantages

• 🧷 Easy-to-solder SO8N package

• 📦 Reels available for pick-and-place machines

Commercial Advantages

• 🚀 Speeds up development

• ⚙️ Faster prototyping

• 🏁 Shorter time-to-market

Pick'n'Place

📦 Reels available at lower prices for high-volume orders. Contact us.

Questions?

💬 Contact us anytime for support.

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This company and the products provided herein are developed independently and are not affiliated with, endorsed by, or associated with any official protocol or standardization entity. All trademarks, names, and references to specific protocols remain the property of their respective owners.