Data Sheet
Modbus TCP/RTU M-bus Gateways (G20, G30)
G30 |
Features
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Introduction
The G20 and G30 are reliable M-Bus to Modbus gateways. They enable seamless integration between M-Bus slave devices and Modbus-based systems. On the M-Bus side, the gateway communicates in master mode and supports up to 10 simultaneously connected slave devices. On the Modbus side, the collected data is made available via the Modbus protocol, ensuring easy and efficient integration with PLCs, SCADA systems, or building automation. Dedicated EMC integrated circuits guarantee stable operation and improved communication quality by reducing interferences typical of industrial environments.
Specifications
Redisage PN |
G20 |
G30 |
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Converter ports | Serial | 1 x active RS232/RS485 |
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M-Bus | 1 x M-Bus master with up to 10 x slaves |
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Microcontroller | ESP32 |
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Wi-Fi | N/A | 802.11 b/g/n | |
Power |
Voltage |
12-30 VDC |
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Power | < 1 W |
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Frame ground connection | yes |
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Serial |
RS232 | TxD, RxD, GND |
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RS485 | A, B |
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M-Bus | MBus+, MBus - |
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Baud rate |
up to 9600 bps |
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LED indicators | communication Tx, Rx, power |
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RS232 OK |
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RS485 termination | 120 |
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3000 VDC isolation side | RS232/RS485 | ||
Connector |
RS232 | 3-pin terminal block max. 2.5 mm2 wire |
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RS485 | 3-pin terminal block max. 2.5 mm2 wire |
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Power | 3-pin terminal block max. 2.5 mm2 wire |
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M-Bus | 3-pin terminal block max. 2.5 mm2 wire |
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Ethernet | RJ45 Fast Ethernet 10/100 Mb/s |
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Transmission |
RS485 |
max. 1,200 m at 9.6 kbps; max. 400 m at 115.2 kbps |
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RS232 | max. 15 m at 115.2 kbps |
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M-Bus | see: M-Bus max. transmission distance (below) |
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Mounting and enclosure | DIN rail, plastic PA - UL 94 V0, black/green |
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Temperatures | -40°C to +75°C operating and storage |
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Humidity | 10 - 90% RH, non-condensing |
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ESD protection |
±4 kV contact discharge / ±8 kV air discharge |
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Certification | CE, RoHS, EMC, LVD, RED |
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Norms |
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M-Bus max. transmission distance
Frame ground FG
Electronic circuits are constantly prone to electrostatic discharge ESD. Redisage Electronics modules feature a design for the frame ground terminal block FG. The frame ground provides a path for bypassing ESD, which provides enhanced static protection ESD abilities and ensures the module is more reliable. Connecting FG terminal block to the earth ground will bypass the ESD disturbances outside the device so will provide a better level of protection against ESD.
Frame Ground FG connection reference drawing is provided below.

If earth ground is not availableavailable, FG can be left floatingfloating, or it can be connected with the power supply GND.
Variants
G20 - M-Bus to Modbus Gateway (1x RS232/RS485)

G30 - M-Bus to Modbus Gateway (1x RS232/RS485) + Wi-Fi

In the G20 and G30 gateways, user should use only RS232 or only RS485 interface of one port as they occupy the same internal bus of the device. It means, don't use RS232 & RS485 at the same time!
LED indicators
G20 | G30 |
M-Bus to Modbus gateways G20 & G30 have 6 LED indicators:
- RX LED - Receiving data
- TX LED - Transceiving data
- PW LED - Power (M-Bus Converter)
- PW LED Blue - Power (Gateway)
- ETH LED Green - Network activity
- ST LED Orange - USB-UART Serial console mode
Pin assignments
G20 | G30 |
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Enclosure dimensions
Additional notes
Related information and links |
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Ordering information | Accessories | Similar products |
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DISCLAIMER NOTES
ALL PRODUCT, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE TO IMPROVE RELIABILITY, FUNCTION OR DESIGN OR OTHERWISE.
Datasheet-ID:
SR-D