The HD67029-xxx are M-Bus / Modbus Slave converters.
They allow to monitor M-Bus slaves with a Modbus Master net (like a PLC etc).

On M-Bus side, the HD67029 can manage up to 250 meters.

The HD67059-xxx are M-Bus / Modbus Master converters.
They allow to insert some Modbus devices in a M-Bus network.

The HD67063 is a M-Bus Multi-Master / Modbus Converter, it allows to interface up to 250 M-Bus devices with a M-Bus Master and a Modbus Master. This converter acts as Splitter and allows to insert a Modbus control system in an already working M-Bus network, maintaining unchanged its functioning.

The HD67076-USB-B2-xxx are M-Bus / Modbus Slave converters.
They allow to monitor M-Bus meters (like Engelmann, Amber-Wireless, Maddalena, Siemens, exc. meters) with a Modbus Master net (like a PLC etc).

Modbus connection is done over USB.

On M-Bus side, the HD67076 can manage up to 250 meters.