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Communication Interfaces
The iCartridge 2.0 supports three communication interfaces: Modbus RTU over RS485, USB CDC serial, and Bluetooth Low Energy (BLE).
Modbus RTU (RS485)
The primary industrial interface is Modbus RTU over RS485. The device operates as a Modbus slave on the network.
Configuration
| Parameter | Value |
|---|---|
| Physical Layer | RS485 (half-duplex) |
| Protocol | Modbus RTU |
| Role | Slave |
| Slave ID | 0x66 (102 decimal) |
| Baud Rate | 115200 bps |
| Data Bits | 8 |
| Parity | None |
| Stop Bits | 1 |
| Flow Control | None (RS485 direction controlled via DE/RE pins) |
Supported Modbus Functions
| Function Code | Description |
|---|---|
0x01 | Read Coils |
0x02 | Read Discrete Inputs |
0x03 | Read Holding Registers |
0x04 | Read Input Registers |
0x05 | Write Single Coil |
0x06 | Write Single Holding Register |
RS485 Connector
The RS485 interface is exposed via a DB9 (SUB-D) connector on the enclosure.
| DB9 Pin | Signal |
|---|---|
| Pin 1 | RS485 A |
| Pin 5 | GND |
| Pin 6 | RS485 B |
Note on RS232
The current hardware provides RS485 only. RS232 Modbus is not supported on the current revision, but can be added with a hardware change if needed.
Register Map
See the Modbus Register Table for the complete register mapping.
USB Serial (CDC)
The USB interface provides a virtual COM port (CDC) over a standard USB Type A connector on the enclosure. The USB connection is optically isolated via an ADuM4160 isolator.
USB serial supports the same binary command protocol used by BLE, enabling PC-based configuration and monitoring. The device enumerates as a standard USB CDC device -- no special drivers are needed on modern operating systems.
See the BLE / USB CDC Protocol page for the full binary protocol specification with examples.
Bluetooth Low Energy (BLE)
Wireless communication is provided via a DA14531MOD BLE module.
BLE UART Configuration
| Parameter | Value |
|---|---|
| Baud Rate | 115200 bps |
| Data Bits | 8 |
| Parity | None |
| Stop Bits | 1 |
| Flow Control | RTS/CTS |
BLE provides wireless access to all Modbus registers via a custom binary command protocol, supporting both read and write operations. A Ping command must be sent every 5 seconds to maintain the BLE session.
See the BLE / USB CDC Protocol page for the full binary protocol specification with examples.