A compact industrial-grade 16-channel Modbus RTU LED driver module featuring high-current MOSFET outputs, per-bank terminal grouping, wide load voltage range, DIN-rail support, and full configuration via Modbus holding registers. Designed for lighting automation, distributed I/O, and custom control applications.
The Open Modbus OM-16LED is a 16-channel low-side LED driver module intended for industrial automation, lighting control, and distributed I/O networks using Modbus RTU over RS-485. It switches DC LED loads such as LED strips, architectural lighting, and indicator arrays up to 60 VDC at up to 8 A per channel.
The module combines an STM32G474 microcontroller, eight 2EDN7534B dual-channel low-side gate drivers, and sixteen NTMFS4D0N08XT1G N-channel power MOSFETs. This architecture enables reliable, high-current, and scalable LED output control with built-in protection and per-channel MOSFET switching.
The full schematic and BOM are available at:
- Schematic → https://github.com/OpenModbus/OM-16LED/blob/main/assets/schematics.pdf
- BOM → https://github.com/OpenModbus/OM-16LED/blob/main/assets/bom.csv
Check the latest release for more!
- 16 low-side MOSFET output channels
- Up to 8 A per channel, 60 VDC maximum load voltage
- 12 VDC direct input or 15–27 VDC via onboard converter (jumper selectable)
- RS-485 Modbus RTU communication (THVD1450 transceiver)
- Fully configurable serial parameters
- DEGSON 2EDGVC pluggable screw terminals
- DIN-rail mount using UM72S profile
- Compact PCB (100 × 72 mm)
Ideal for:
- LED strip lighting control
- Architectural and mood lighting
- Building automation
- PLC expansion
- Industrial signaling and indicators
- Stage and display lighting
- Custom distributed lighting networks
The STM32G474RETx MCU handles Modbus RTU processing, configuration storage, and output control logic. It is an ARM Cortex-M4 running at up to 170 MHz with 512 KB flash and 128 KB RAM, providing ample headroom for advanced output control features.
Eight 2EDN7534B (Infineon) dual-channel low-side gate drivers control the power MOSFETs. Their key characteristics include:
- 2 channels per IC (8 ICs → 16 channels total)
- 5 A peak gate drive current
- Precise timing and low output resistance
- Designed for reliable switching of high-current loads
Sixteen NTMFS4D0N08XT1G (onsemi) N-channel MOSFETs perform the actual load switching. Their key characteristics include:
- 80 V drain-source breakdown voltage
- High continuous drain current
- SO8FL package
A THVD1450 (Texas Instruments) transceiver provides differential RS-485 communication with:
- ±18 kV IEC ESD protection
- Fail-safe features
- Suitable for long cable runs
The board supports two input modes selected by an onboard jumper:
- 15–27 VDC input — passes through the R-78E12-1.0 step-down regulator (RECOM), which generates the 12 V gate driver supply
- 12 VDC direct input — bypasses the 12 V converter; 12 V is fed directly to the gate drivers
In both modes the R-78E3.3-0.5 step-down regulator (RECOM) generates 3.3 V for the MCU and logic from the main input rail.
- 12 VDC direct input (jumper: bypass mode) or 15–27 VDC input (jumper: converter mode)
- Internal regulated 12 V gate drive supply (converter mode only)
- Internal regulated 3.3 V logic supply
- 16 low-side MOSFET channels
- Up to 60 VDC load voltage
- 80 VDC absolute maximum
- 8 A max per channel
- Channels grouped into 4 banks of 4
- RS-485, 2-wire
- Modbus RTU protocol
- Default settings: 9600 baud, 8N1, address 1
- All communication parameters can be reconfigured via holding registers
- PCB: 100 × 72 mm
- DIN-rail enclosure compatibility: UM72S profile
- DEGSON 2EDGVC pluggable screw terminals
- Mounting suitable for industrial control cabinets
Each output channel is controlled by a per-channel duty cycle value stored in a holding register. The MCU generates a PWM signal accordingly, driving the gate driver and MOSFET to regulate LED brightness. A duty cycle of 0 turns the channel fully off; the maximum value drives it fully on.
To be announced soon.
Configuration registers start at 0x00 and are stored in non-volatile memory.
| Register Address (Hex) | Name | Description | Allowed Values | Default |
|---|---|---|---|---|
| 0 (0x00) | Slave Address | Modbus device ID | 1–247 | 1 |
| 1 (0x01) | Baud Rate Code | Serial speed selector: 0=1200, 1=2400, 2=4800, 3=9600, 4=19200, 5=38400, 6=57600, 7=115200 | 0–7 | 3 |
| 2 (0x02) | Parity | Communication parity | 0=None, 1=Even, 2=Odd | 0 |
| 3 (0x03) | Data Bits | Serial data width | 5–9 (typ. 8) | 8 |
| 4 (0x04) | Stop Bits | Serial stop bits | 1–2 | 1 |
To be announced soon.
The OM-16LED uses low-side (MOSFET) switching. The module connects the LED load to ground when ON; the load must be powered from your external power supply.
The 16 outputs are grouped into four banks of 4 channels (Bank A–D). This allows one board to drive LED loads powered from different voltages simultaneously.
Examples:
- Bank A → 12 V LED strips
- Bank B → 24 V LED strips
- Bank C → 48 V LED channels
- Bank D → 5 V LED indicators
Each output contains a power MOSFET that sinks current:
Load +V ─────── LED Load ─────── OUTx (SINK)
│
└── GND (OM-16LED)
- Connect the load voltage (up to 60 VDC) to the Vx terminal of the bank.
- Connect the output pin (OUTx) to the negative side of the LED load.
- Tie power supply GND to OM-16LED GND.
- Ensure the supply can support the total current of that bank.
- Do not exceed 60 VDC load voltage
- Ensure load currents stay within 8 A per channel
- Maintain proper RS-485 termination and shielding
- Verify adequate heat dissipation when operating at high currents
For questions, feedback, or technical assistance regarding the Open Modbus OM-16LED, the following support channels are available:
For general inquiries, firmware questions, or troubleshooting: contact@sszczep.dev
Issue tracker, source code, hardware design files, and community contributions: https://github.com/OpenModbus/OM-16LED
Share projects, ask for help, or suggest features: https://github.com/orgs/OpenModbus/discussions
Submit issues directly via GitHub Issues: https://github.com/OpenModbus/OM-16LED/issues