3Wire RS2M2 | Dual Master Isolated RS485 Hub
1
Two RS-485 Masters. One Slave Network. No Cross-Interference.
Industrial RS-485 hub for Modbus and master-slave communication systems.
3Wire RS2M2 is a 2-channel isolated RS-485 hub that allows two RS-485 master devices to communicate with one or more RS-485 slave devices without cross-interference.
It ensures that responses from slave devices are sent only to the corresponding master that initiated the request, improving communication control in multi-master RS-485 environments.
RS2M2 is suitable for industrial automation, remote monitoring, alarm systems, access control and other RS-485 control applications.
Why RS2M2?
In many RS-485 networks, one master communicates with many slave devices. But some sites require two master devices, such as a PLC and monitoring system, to access the same RS-485 slave network.
Without proper isolation and communication control, multi-master communication can create collision, interference and unreliable responses.
This makes RS2M2 useful where the same RS-485 device network must be shared between control, monitoring, automation, metering or supervisory systems.
Typical Applications
Industrial Automation
Allow PLCs, controllers and monitoring systems to access RS-485 slave devices with better communication separation.
Modbus RTU Networks
Supports master-slave protocols such as Modbus for industrial metering and control systems.
Energy Management
Share RS-485 digital power meters between automation systems and energy monitoring platforms.
BMS and Facility Systems
Useful where BMS, EMS or SCADA systems need access to the same RS-485 slave device network.
Alarm and Access Control
Suitable for RS-485 based alarm systems, access control networks and site monitoring systems.
Remote Monitoring
Supports RS-485 communication sharing for remote monitoring and control applications.
Key Features
Dual RS-485 Master Support
Allows two RS-485 master devices to communicate with one or more slave devices.
Controlled Response Routing
Responses from slave devices are sent only to the master that initiated the request.
Protocol Compatibility
Supports master-slave protocols such as Modbus and similar RS-485 communication systems.
Independent Port Configuration
Each communication port can be configured independently for baud rate and communication format.
High Slave Node Capacity
The slave communication port supports connection to multiple slave devices.
LED Port Indicators
Each of the three communication ports includes LED indication for real-time monitoring.
Protection and Reliability
Photoelectric Isolation
Provides robust signal integrity and helps protect communication circuits from electrical disturbance.
15kV ESD Protection
Signal interface includes anti-static protection for industrial RS-485 environments.
5kA Lightning Surge Protection
Built-in anti-lightning and anti-surge protection helps safeguard connected systems.
Power Protection
DC 9–30V input with built-in overcurrent and reverse polarity protection.
Dual Electrical Isolation
Complete electrical isolation between communication and power, plus full isolation between master and slave interfaces.
High-Performance Architecture
Built with a 32-bit microcontroller and high-speed optocouplers for stable performance.
Communication Interface
RS2M2 includes three RS-485 communication interfaces:
MA1
RS-485 Master 1 interface for the first master device.
MA2
RS-485 Master 2 interface for the second master device.
SLA
RS-485 slave interface for one or more connected slave devices.
- “A” terminal connects to device RS-485 “A”
- “B” terminal connects to device RS-485 “B”
- “GND” terminal connects to grounding port
- Transparent data transmission
- Software adjustable baud rate
- Software adjustable communication format
Technical Highlights
| Parameter | RS2M2 Specification |
|---|---|
| Product Type | Dual master isolated RS-485 hub |
| Master Interfaces | MA1 and MA2 for RS-485 master devices |
| Slave Interface | SLA for RS-485 slave devices |
| Communication Type | Master-slave protocols, including Modbus and similar protocols |
| Data Transmission | Transparent transmission |
| Baud Rate | 1200 bps to 115200 bps; default 9600 bps |
| Communication Format | Stop bit, bit length and parity can be configured |
| Slave Node Capacity | Supports multiple slave devices; slave port supports up to 175 nodes depending on network conditions |
| Protection Level | RS-485 interface protection with 600W surge protection and ±15kV ESD protection |
| Electrical Isolation | Communication and power isolation; master and slave interface isolation |
| Power Input | DC 9–30V |
| Minimum Required Current | ≥100mA |
| Maximum Voltage Limit | Do not exceed 35V |
| Power Protection | Built-in reverse polarity protection and overcurrent protection |
| Processor Architecture | 32-bit microcontroller with high-speed optocouplers |
| Status Indicators | LED indicators for communication ports and status monitoring |
Wiring and Power Summary
Power Input
Connect VCC to the positive terminal of the DC 9–30V power supply and GND to the negative terminal.
RS-485 Wiring
Connect terminal A to the RS-485 A line, terminal B to the RS-485 B line, and GND to signal ground where required.
SET Button
The SET terminal/button is used for configuration setting as part of the RS2M2 interface arrangement.
Product Summary
3Wire RS2M2 is a dual master isolated RS-485 hub designed to allow two RS-485 master devices to communicate with one or more slave devices while reducing cross-interference.
With photoelectric isolation, 15kV ESD protection, 5kA lightning surge protection, independent port configuration, transparent transmission and DC 9–30V power input, RS2M2 is suitable for industrial automation, metering, access control, alarms and remote monitoring applications.
Contact 3Wire / Saturn Pyro for product selection, wiring support and RS-485 communication application guidance.
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