MR004W RS232C and RS485 to M-Bus level converter for 60 slaves

MR004W provides transparent access to the M-Bus through RS232C and RS485.

MR004W is an industrial M-Bus level converter designed for cooperation with external controllers, PCs, laptops and building control systems. The device converts signals from RS232C or RS485 interfaces into M-Bus signals, providing transparent access to the M-Bus from a higher-level controller. The manual describes the unit as a Level Converter for 60 slaves with RS232C and RS485 interface. 

MR004W allows remote powering and readout of up to 60 M-Bus slaves, each with a standard load of 1.5 mA. The device is fully transparent, which means that the external controller must run software capable of handling the communication protocols of the connected meters. This makes MR004W a technical interface converter for M-Bus networks rather than an autonomous local display terminal. 

Communication interfaces.

The unit is equipped with both RS232C and RS485 interfaces, which allows integration with different controller types and supervisory systems. For RS232, the TXD, RXD and GND signals are available on terminals and on the DB9 connector of the housing. The manual also states that only one RS232 connection method may be used at the same time, and that the simultaneous use of RS485 and RS232 can cause temporary communication disturbances. 

Operational reliability and protection.

MR004W has been designed for reliable operation in M-Bus installations. The product sheet lists galvanic insulation, bit-recovery, suppression of echo, collision detect, permanent safety against short-circuit and automatic response to overcurrent situations. Device status is indicated by four LEDs: Power, Slave, Max and Short. 

Product features.

• RS232C / RS485 to M-Bus level converter for 60 slaves.
• Supports up to 60 standard M-Bus unit loads.
• Transparent communication for external controllers.
• RS232C interface with terminal and DB9 connection.
• RS485 interface for supervisory system integration.
• Galvanic insulation.
• Bit-recovery and suppression of echo.
• Collision detect and overcurrent protection.
• Permanently safe against M-Bus short-circuit.
• Integrated power supply.

Technical specification.

• Device type: M-Bus Level Converter for 60 slaves
• Interfaces: RS232C, RS485, M-Bus
• Maximum number of slaves: 60 unit loads
• Power supply: 230VAC, 50Hz, 25W
• US version: 110VAC, 50Hz, 25W
• Operating temperature: 0 to +45°C
• Storage temperature: -10 to +60°C
• Humidity: 10 to 70%, non-condensing
• Dimensions: 166 x 190 x 112 mm
• Protection class: IP53, cable glands must be closed
• Material / colour: PS / light-grey, similar to RAL 7035
• Weight: 1.3 kg
• Bus voltage mark at 0 mA: 38.5 to 39.5 V
• Voltage drop for space: 12 to 13 V
• Warning current level Max LED: 90 to 110 mA
• Level for overcurrent interruption Short LED: 130 to 160 mA
• Level for bit detection from slave: 7 mA
• Level for collision detect: 30 mA

The manual also states that the device transmits a break signal for at least 50 ms after a collision and for at least 100 ms after a short circuit. MR004W complies with EN1434-3 for M-Bus and is suitable for installations where a stable and technically straightforward M-Bus converter is required for integration through RS232C or RS485. 

Need help selecting the right M-Bus converter or planning an M-Bus readout system? Contact our consultant: CONTACT