MR005 IR M-Bus level converter master for 3 devices with RS232C and ZVEI IR optical

MR005 IR – compact PW3 M-Bus master level converter for up to 3 devices, with RS232C and optical interface.

MR005 IR is a compact M-Bus level converter (master) designed for remote powering and remote reading of up to 3 M-Bus slaves (standard unit loads), such as water, heat, electricity or gas meters, and pulse meters. The device is based on the PW3 platform and is tailored for small, cost-effective M-Bus installations where easy integration, stable bus operation and quick diagnostics matter.

Use cases in small M-Bus installations and service

MR005 IR is a practical choice whenever you need central readout of a small number of meters with a single compact master: local metering points, small technical nodes, test rigs, commissioning and service work. It also fits projects where you want to avoid a permanently installed PC in the cabinet and perform periodic readouts with a handheld terminal.

Communication interfaces: RS232C + ZVEI optical IR

MR005 IR provides an RS232C interface for data requests and processing of response telegrams from the M-Bus network. RXD, TXD and GND are available on both screw terminals and the front DB9 connector, and echo is suppressed. Please note that the RS232C interface is not galvanically isolated from the power supply and the M-Bus. If electrical isolation is required, the optical interface can be used instead. The MR005 IR variant includes an additional ZVEI-compliant optical interface for convenient readout using ZVEI optical heads. To reduce interference, external light suppression is implemented, and only 300..2400 Baud are guaranteed on the optical interface.

Reliable operation and LED diagnostics

The device is resistant to sustained short circuit on the M-Bus and includes overcurrent interruption (threshold approx. 50..70 mA, shortest switch-off time approx. 50 ms). Status LEDs provide fast field diagnostics: On (supply voltage applied), Short (overcurrent/short-circuit), and Slave (slave transmitting), which accelerates commissioning and troubleshooting.

M-Bus parameters and wiring range

MR005 IR supports M-Bus transmission speeds of 300..9600 Baud and provides a bus quiescent voltage of about 30.5 V ±5%. The unit has three terminal pairs M+/M- to help separate lines; polarity is irrelevant in M-Bus installations. Total wiring capacity affects signal quality, so achievable network expansion depends on baud rate (example cable: JYSTY nx2x0.8): > 1000 m at 9600 Bd, > 4000 m at 2400 Bd, > 12000 m at 300 Bd. With 3 slaves, the maximum distance to a meter can reach approx. 7000 m (depending on cable resistance and resulting voltage drop).

Mounting, housing and power supply

MR005 IR is intended for TS35 DIN rail mounting (DIN EN 50022); the fixture can also be removed and used for wall mounting. The housing is IP20, made of ABS (RAL 7035), with dimensions approx. 78 × 56 × 118 mm. Thanks to a wide supply range, you can often reuse an existing cabinet PSU: 10..27 VAC or 10.5..28 VDC. Operating temperature range is 0..55°C.

MR005 IR is a compact and robust M-Bus master for up to 3 devices, combining RS232C integration with convenient ZVEI optical readout. It is an excellent fit for small installations and service scenarios where short-circuit resilience, clear LED diagnostics and flexible power supply simplify deployment.

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