Glossary term
Modbus
protocoleBasics
Also known as
Modbus RTUModbus TCPModbus ASCII
Definition
Serial communication protocol published in 1979 by Modicon, now a de facto standard for industrial automation. Based on a master/slave model with addressable registers; available as Modbus RTU (binary), ASCII and TCP/IP.
Questions using this term
- A Modbus RTU bus on RS-485 supports up to 32 nodes per segment (extendable with repeaters), requires 120 ohm termination resistors at both ends of the bus, and biasing resistors to define the idle state.3. Modbus RTU · RS-485 Multi-Drop
- Modpoll (focus-sw.com) and mbpoll (Linux/macOS) are free command-line tools used to query a Modbus slave from a PC, indispensable for Modbus diagnostics and integration commissioning.6. Practical · Modpoll / mbpoll
- Most modern industrial variable-frequency drives (VFDs) such as ABB ACS, Schneider Altivar, Siemens SINAMICS and Danfoss VLT support Modbus RTU and/or TCP as a control interface, with a register map documented by the manufacturer.11. Practical · Antriebsanbindung
- Smart pumps such as the Grundfos MAGNA3 and the Wilo Stratos MAXO natively support Modbus RTU/TCP, exposing around 50 parameters (power, flow, temperature, status, alarms) and accepting commands (speed, mode), which enables BMS integration without a separate external drive.24. Use cases · Pumpen und Antriebe
- PROFIBUS DP has no native security (no encryption, no authentication); defence relies entirely on the physical isolation of the bus (dedicated RS-485 segment, not connected to a general-purpose network).15. Security · Keine native Security
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