Product Overview
The Ebyte MA01 series is an industrial-grade RS485 serial I/O networking module (Remote I/O) supporting the standard ModBus-RTU communication protocol. Available in 1DI+1DO to 4DI+4DO configurations, it enables remote digital input acquisition and relay output control via RS485 bus — compatible with PLC, SCADA, configuration software, and host computers.
- Interface: RS485, ModBus-RTU protocol
- I/O: 1–4 channel dry-contact DI + 1–4 channel C-type relay DO (Hongfa genuine relay)
- Power Supply: DC 8–28V, 50mA @12V
- Operating Temp: -40℃ to +85℃, 5–95%RH (non-condensing)
- Installation: DIN rail + positioning hole
- Protection: Triple-proof coating (anti-mold, anti-humidity, anti-salt spray)

Model Selection & Specifications
| Model | DI Channels | DO Channels | Size (mm) | Weight |
|---|---|---|---|---|
| MA01-AXCX1010-V2P | 1 | 1 | 54×90×32 | 75±5g |
| MA01-AXCX2020-V2P | 2 | 2 | 90×90×40 | 123±5g |
| MA01-AXCX3030-V2P | 3 | 3 | 90×90×40 | 134±5g |
| MA01-AXCX4040-V2P | 4 | 4 | 115×90×40 | 165±5g |
| MA01-AXCX1010-V2 | 1 | 1 | 54×90×32 | 74±5g |
| MA01-AXCX2020-V2 | 2 | 2 | 90×90×40 | 121±5g |
| MA01-AXCX3030-V2 | 3 | 3 | 90×90×40 | 133±5g |
| MA01-AXCX4040-V2 | 4 | 4 | 115×90×40 | 164±5g |
V2P = triple-proof coating version; V2 = standard version

Technical Specifications
| Category | Parameter | Value |
|---|---|---|
| Power Supply | Operating Voltage | DC 8–28V |
| Working Current | 50mA @12V | |
| Power Indicator | Green LED | |
| RS485 Serial Port | Communication Interface | RS485 |
| Baud Rate | 1200–115200 bps (default 9600 bps) | |
| Data Bits | 8 (fixed) | |
| Parity | None / Odd / Even (default: None) | |
| Stop Bits | 1 (fixed) | |
| Protocol | ModBus RTU | |
| Device Address | 0–255 (default 1; 0 = broadcast) | |
| Comm Indicator | Red LED flashes at 60ms period | |
| DI Input | Channels | 1 / 2 / 3 / 4 (model-dependent) |
| Interface Type | Dry contact | |
| Trigger Mode | Rising edge / Falling edge / Level (default: rising edge) | |
| Filter Parameter | 1–16 (default 6) | |
| Sampling Frequency | 1 kHz | |
| DO Output | Channels | 1 / 2 / 3 / 4 (model-dependent) |
| Output Type | C-type relay (NO + NC), Hongfa genuine | |
| Output Mode | Level / Pulse / Follow / Cycle | |
| Contact Capacity | 30V/10A DC; 250V/10A AC | |
| Output Indicator | Red LED per channel | |
| Environment | Operating Temp/Humidity | -40–+85℃, 5–95%RH (non-condensing) |
| Storage Temp/Humidity | -60–+125℃, 5–95%RH (non-condensing) | |
| Installation | DIN rail + positioning hole |
Key Features
Standard ModBus-RTU Protocol — Plug-and-Play Integration
Fully compliant with the ModBus-RTU standard. Directly readable by mainstream PLCs (Siemens, Mitsubishi, Omron), SCADA systems, and configuration software without custom drivers. Device address range 0–255 supports multi-drop RS485 bus topology.
Hongfa Genuine Relay — High-Reliability DO Output
Each DO channel uses an authentic Hongfa C-type relay rated at 30V/10A DC or 250V/10A AC. Supports four output modes: Level, Pulse, Follow, and Cycle — covering the full range of industrial switching scenarios.
High Protection & Strong Isolation Design
V2P variants are coated with triple-proof paint (anti-mold, anti-humidity, anti-salt spray). Optical isolation between RS485 bus and I/O channels prevents ground loops and surge damage in harsh industrial environments.
Four DO Output Modes for Flexible Control
Level mode for sustained on/off; Pulse mode for timed momentary switching; Follow mode mirrors DI input state; Cycle mode for periodic toggling — all configurable via ModBus registers without firmware changes.
Built-in Watchdog & Communication Timeout Reset
Hardware watchdog prevents system lockup. Configurable communication interruption timeout automatically resets DO outputs to a safe state when the host loses connection — critical for unattended remote installations.
Industrial-Grade Quality & Easy Maintenance
Rated -40℃ to +85℃ for full industrial temperature range. One-button parameter reset restores factory defaults. Supports in-field firmware upgrade via RS485 without disassembly.
DIN Rail & Positioning Hole Mounting
Standard DIN rail clip plus positioning holes for panel or cabinet mounting. Compact footprint from 54×90×32mm (1010) to 115×90×40mm (4040) fits standard control enclosures.
Ideal Applications
- Industrial Automation: PLC remote I/O expansion, converter & sensor status acquisition, relay control
- Building Automation: Access control, HVAC switching, lighting control via RS485 bus
- Energy & Utilities: Circuit breaker status monitoring, pump/valve control, substation automation
- Smart Agriculture: Irrigation valve control, greenhouse environment switching
- Logistics & Infrastructure: Gate/barrier control, alarm input collection, status telemetry


FAQ
Q: Is the MA01 compatible with Siemens, Mitsubishi, or Omron PLCs?
A: Yes. The MA01 implements standard ModBus-RTU over RS485. Any PLC or master device with a ModBus-RTU master function can read DI status and write DO commands directly using the published register map — no custom driver required.
Q: What is the difference between V2 and V2P variants?
A: V2P adds a triple-proof conformal coating (anti-mold, anti-humidity, anti-salt spray) over the PCB, making it suitable for outdoor enclosures, coastal environments, or high-humidity industrial sites. Electrically and functionally identical to V2.
Q: How many MA01 modules can be connected on one RS485 bus?
A: Up to 255 devices (addresses 1–255) can share one RS485 bus. Address 0 is reserved as the broadcast address. Recommended maximum bus length is 1200m at 9600 bps with proper termination resistors.
Q: What happens to the relay outputs if RS485 communication is lost?
A: The built-in communication timeout watchdog detects bus silence and automatically resets all DO outputs to a configurable safe state (default: all relays open). This prevents uncontrolled actuator states during network faults.
Q: Can the baud rate and device address be changed in the field?
A: Yes. Baud rate (1200–115200 bps) and device address (1–255) are configurable via ModBus holding registers or the Ebyte configuration tool over RS485. A hardware reset button restores factory defaults (9600 bps, address 1) without a PC.