Modbus RS485 master - KNX Gateway

Code: EK-BH1-TP-485

Description

The Ekinex® Modbus RS485 - KNX Gateway performs a protocol conversion between a serial RS485 Modbus RTU and a KNX TP network. The device works as Modbus master. The device integrates a KNX bus communication module and is suitable for mounting on a 35 mm DIN rail; it requires an auxiliary power supply.

The device manages a two-way data stream: the Modbus registers can be cyclically read and their value sent as a communication object over the KNX TP network through a multicast communication to configured group addresses. The data update over the KNX network can be done cyclically and/or on event of change of the data acquired by the Modbus network.

Likewise, the Ekinex gateway can make requests to cyclically read KNX communication objects or acquire their values during data exchange over the bus. Cyclically or on event of change of the communication objects, data are written to the Modbus registers of one or more configured devices. It supports reading and writing 1-bit registers (Coil and Status), 16-bit registers (Holding and Input) as well as 32-bit floating point registers (IEEE 754 format).

Modbus Standard Compatibility

Modbus® is an open source, standard communication protocol suitable for master/slave data exchange between smart devices in various applications, such as industrial production, infrastructure, transportation and energy management.

Technical Data

Power Supply and Absorption

Power Supply8...24 Vac or 12...35 Vdc

Absorption at 24 Vdc3.5 VA

KNX Communication Parameters

KNX PortKNX TP (Twisted Pair), electrically isolated from power supply

Baud Rate9600 baud

Buffer Memory1440-byte volatile support 'KNX image' memory buffer

Communication Objects1-bit, 1-byte, 2-byte and 4-byte objects (including DPT 9.xxx float conversion)

Modbus RS485 Communication Parameters

Serial PortRS485 serial port, electrically isolated from power supply

Termination Resistance120 Ω termination resistance insertable by a 1-way microswitch

ProtocolModbus Master RTU

Baud RateSelectable from 1200 to 115200 baud

Device AddressingAddressing from 0 to 250

Supported RegistersCoil, Input, Holding Register and Input Register

Buffer Memory1440-byte volatile support 'Modbus image' memory buffer

Design and Physical Characteristics

Housing MaterialPlastic casing

Modular Width4 modular units (4 MU = 72 mm)

Mounting35 mm DIN rail (EN 60715)

Device Weight145 g

Protection DegreeIP20 (installed device)

Delivery

The delivery includes the device and terminal blocks to connect to the KNX bus.

Functions and Features

Bidirectional protocol conversion between Modbus RTU RS485 and KNX TP bus

Operates as Modbus RTU master addressing up to 250 slave devices

Single and multiple register read/write for Coil, Input, Holding and Input registers

Support for 32-bit floating point registers (IEEE 754) and DPT 9.xxx KNX conversion

Configurable cyclic updates or event-driven change transmission

Switchable 120 Ohm termination resistor on the RS485 line

Ethernet connection for seamless configuration via CGEKBH1TP485 PC software

Configuration and Commissioning

Configuration and commissioning require the dedicated PC application software CGEKBH1TP485 communicating with the gateway via its integrated Ethernet port.