MergenHub Modbus TCP, RTU and ASCII support
The most widespread field protocol in industry. MergenHub connects Modbus devices over both Ethernet and serial, with complete support for addressing and function-code details.
The MergenHub interface — live register values, address format and write function codes for a Modbus device on one screen.
What is Modbus?
Modbus is an open master/slave protocol used by PLCs, RTUs, meters, drives and I/O modules to share data. It reads and writes across coil and register areas (0x/1x/3x/4x); Modbus TCP runs over Ethernet with an MBAP header, while Modbus RTU/ASCII runs over serial links.
Where is it used?
Water/wastewater pump stations, energy meters, variable-frequency drives, compact PLCs and field I/O. The vast majority of field devices speak Modbus, so it is the usual starting point for most integrations.
Feature coverage
Modbus address formats and function codes are supported so existing projects migrate one-to-one.
FC05 / FC06 / FC16 / FC22
Single coil (FC05), single register (FC06), multiple registers (FC16) and masked write (FC22) — function code chosen to match device expectations.
Zero / one based
Zero-based and one-based addressing; 5/6-digit Modicon address formats and direct register numbers supported together.
TCP · RTU · ASCII · UDP
Modbus TCP, serial RTU/ASCII and UDP transport. Serial links can also be tunnelled over TCP/IP (Ethernet Encapsulation).
Word/bit order
Modicon word and bit order options (including FirstWordLow); correct byte layout for 32/64-bit integers and floats.
Per-block reads
Per-area maximum read block size — devices that cannot handle large blocks are polled without resetting.
One socket per channel
One socket per channel, block isolation and quarantine so one device fault never disturbs its neighbours.