BC7300 | Modbus Bus Terminal Controller

The Bus Terminal Controller BC7300 is a Bus Coupler with integrated PLC functionality and has a fieldbus interface for Modbus. The BC7300 is an intelligent slave and can be used as a non-central intelligence in the Modbus system. One unit consists of the Bus Terminal Controller, any number of terminals between 1 and 64, and a bus end terminal. Because of the low baud rate used by the Modbus protocol, use of the BC7300 may be of value to reduce the bus communication. Time-critical connections can also be programmed directly at the Bus Terminal Controller.

The Bus Terminal Controller is programmed using the TwinCAT programming system according to IEC 61131-3. The configuration/programming interface on the BC7300 is used to load the PLC program.

The inputs and outputs of the connected Bus Terminals are assigned in the PLC’s default setting. Each Bus Terminal can be configured in such a way that it exchanges data directly through the fieldbus with the higher-level automation device. Similarly, pre-processed data can be exchanged between the Bus Terminal Controller and the higher-level controller via the fieldbus. Configuration is performed using the KS2000 configuration software.

Controller for distributed signal processing

The programming system TwinCAT for the BC7300 operates, independently of the manufacturer, in accordance with IEC 61131-3. The PLC programs can be written in five different programming languages (IL, FBD, LD, SFC, ST). In addition, TwinCAT offers extensive debug functionalities (breakpoint, single step, monitoring, …), which facilitate commissioning. It is also possible to perform adjustment and measurement of the cycle time.

PLC data	Modbus | BC7300
Programming	TwinCAT (via programming interface or fieldbus)
Program memory	32/96 kbytes
Data memory	32/64 kbytes
Remanent data	512 bytes
Runtime system	1 PLC task
PLC cycle time	approx. 3 ms for 1,000 instructions (without I/O cycle, K-bus)
Programming languages	IEC 61131-3 (IL, LD, FBD, SFC, ST)
Online change	–

Technical data	BC7300
Number of Bus Terminals	64
Max. number of bytes fieldbus	512 byte input and 512 byte output
Digital peripheral signals	256 inputs/outputs
Analog peripheral signals	128 inputs/outputs
Protocol	RTU/ASCII (default: RTU)
Configuration possibility	by rotary switch or KS2000
Data transfer rates	150, 300, 600, 1200, 2400, 4800, 9600, 19,200, 38,400 baud (default: 9600 baud)
Bus interface	D-sub 9-pin, RS485
Power supply	24 V DC (-15 %/+20 %)
Input current	70 mA + (total K-bus current)/4, 500 mA max.
Starting current	2.5 x continuous current
Recommended fuse	≤ 10 A
Current supply K-bus	1750 mA
Power contacts	24 V DC max./10 A max.
Electrical isolation	500 V (power contact/supply voltage/fieldbus)
Weight	approx. 170 g
Operating/storage temperature	0…+55 °C/-25…+85 °C
Relative humidity	95 %, no condensation
Vibration/shock resistance	conforms to EN 60068-2-6/EN 60068-2-27
EMC immunity/emission	conforms to EN 61000-6-2/EN 61000-6-4
Protect. class/installation pos.	IP 20/variable
Approvals	CE, UL, Ex, GL

Accessories
KS2000	configuration software for extended parameterisation
TX1200	programming system conforms to IEC 61131-3
Cordsets	cordsets and connectors

Related products
BK7300	Modbus Bus Coupler for up to 64 Bus Terminals
BK7350	Modbus “Compact” Bus Coupler for up to 64 Bus Terminals (255 with K-bus extension)

System
Modbus	For further Modbus products please see the system overview