Beckhoff BK7300 Modbus Bus Coupler

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Manufacturer: BECKHOFF
Product No.: BK7300
Country of origin:Germany
Product Type: Bus Couplers
Payment: T/T, Western Union
Weight: 170g
Shipping port: Xiamen
Warranty: 12 months

Description

Integrating modular I/O systems directly with serial networks, the BK7300 Modbus RTU/ASCII Bus Coupler establishes a reliable interface between the Modbus fieldbus and decentralized Beckhoff Bus Terminals. This communication interface links up to 64 standard Bus Terminals to a central controller via an RS485 connection. It automatically detects connected terminal channels and structures them into the process image, enabling efficient handling of digital, analog, and specialized inputs and outputs.

The BK7300 coupler operates on Modbus RTU or Modbus ASCII protocols, which are configurable using rotary address switches or the proprietary KS2000 software tool. Designed for harsh industrial environments, this unit features a compact, DIN-rail mountable form factor and provides 500 V electrical isolation between the power contacts, the fieldbus interface, and the internal K-bus electronics.

Features

Direct integration of up to 64 standard Beckhoff Bus Terminals.
Supports both Modbus RTU and Modbus ASCII protocols (RTU default setting).
Flexible node addressing via hardware rotary switches or software configuration.
Generous process image capacity supporting up to 512 bytes of input and 512 bytes of output data.
Robust RS485 serial interface housed in a standard D-sub 9-pin connection.
Integrated K-bus power supply providing up to 1750 mA current output for terminal electronics.

Applications

Decentralized process automation and plant control.
Factory automation and production assembly lines.
Building automation, HVAC, and utility monitoring networks.
Industrial machinery control with modular diagnostic demands.

Technical Specifications

Manufacturer	Beckhoff Automation
Part Number / Model	BK7300
Product Type	Modbus Bus Coupler
Protocol	Modbus RTU / Modbus ASCII (default: RTU)
Bus Interface	D-sub 9-pin (RS485)
Number of Bus Terminals	64 (up to 255 with K-bus extension)
Max. Process Image Size	512 bytes input / 512 bytes output
Digital Peripheral Signals	512 inputs/outputs
Analog Peripheral Signals	256 inputs/outputs
Configuration Interface	Rotary switch or KS2000 configuration software
Power Supply Voltage	24 V DC (-15% / +20%)
Input Current	70 mA + (total K-bus current)/4 (max. 500 mA)
Starting Current	2.5 x continuous current
Recommended Fuse Protection	Less than or equal to 10 A
Current Supply K-Bus	1750 mA
Power Contacts Voltage	24 V DC max.
Power Contacts Current	10 A max.
Electrical Isolation	500 V (power contacts / supply voltage / fieldbus)
Weight	Approx. 170 g
Operating Temperature	0 to +55 degC
Storage Temperature	-25 to +85 degC
Relative Humidity	95%, non-condensing
Vibration Resistance	Conforms to EN 60068-2-6
Shock Resistance	Conforms to EN 60068-2-27
EMC Immunity / Emission	Conforms to EN 61000-6-2 / EN 61000-6-4
Protection Class	IP20

Connections and Interfaces

D-sub 9-Pin Pinout	Signal Assignment (RS485)
Pin 1	Shield (Screen)
Pin 3	RxD/TxD-B (Positive Data Line)
Pin 5	GND (Signal Ground)
Pin 6	VP (+5 V supply for active termination)
Pin 8	RxD/TxD-A (Negative Data Line)

Installation Guidelines

Mount the coupler horizontally on standard 35 mm DIN rails conforming to EN 60715.
Ensure an adequate ventilation gap above and below the module to allow convection cooling.
Ensure the system power is completely disconnected before inserting or removing any Bus Terminals or changing wiring.
Connect the PE (Protective Earth) contact directly to the DIN rail to maintain low-impedance grounding.
Ensure active RS485 termination resistors are installed at both physical ends of the Modbus segment.

Compliance and Certifications

CE
UL (cULus)
Explosion Protection (Ex)
Germanischer Lloyd (GL)

Key Features:

What communication protocols does the BK7300 support?

The BK7300 supports Modbus RTU and Modbus ASCII. Modbus RTU is configured as the default setting.

How do you set the station address on the BK7300?

The station address and network configuration can be set manually via the integrated rotary address switches on the unit or digitally via the KS2000 configuration software.

What is the maximum K-bus current supply of the BK7300?

The BK7300 has a maximum K-bus current supply capacity of 1750 mA (1.75 A) for the downstream terminal modules.

What type of connection interface is used for the fieldbus on this module?

The fieldbus interface uses a standard 9-pin female D-sub connector utilizing an RS485 serial connection.

How many Bus Terminals can be connected to a single BK7300 coupler?

Up to 64 standard Bus Terminals can be connected directly. This number can be expanded up to 255 using K-bus extension terminals.

Global Express Shipping

Standard Delivery: 4-6 Business Days via DHL, FedEx, and UPS.
Express Dispatch: Same-day dispatch for in-stock orders placed before 2:00 PM (GMT+8).
Worldwide Coverage: Serving over 150 countries, including rapid delivery to Saudi Arabia and UAE.

Returns & Warranty

30-Day Guarantee: Returns accepted for in-stock products in original, factory-sealed packaging.
12-Month Warranty: Every industrial component is backed by our professional technical warranty.

Orders are processed and delivered Monday-Friday (excluding public holidays).

For full eligibility, restocking fees, and international return details, please view our official Refund & Return Policy .

TECHNICAL SPECIFICATIONS

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Beckhoff BK7300 Modbus Bus Coupler