Modbus Interface

Address

Description

0x0000
0x00FF

Process data interface
inputs

0x0800
0x08FF

Process data interface
outputs

0x1000
0x1006

Read only

Coupler Fieldbus Box code

0x100A

2 Byte PLC interface

0x100B

terminal diagnostics

0x100C

coupler status

0x1010

length of process image in Bit, analog outputs (without PLC variables)

0x1011

length of process image in Bit, analog inputs (without PLC variables)

0x1012

length of process image in Bit, discrete outputs

0x1013

length of process image in Bit, discrete inputs

0x1020

Watchdog, current time in [ms]

0x110A

Read/Write

2 Byte PLC Interface

0x110B

terminal diagnostics

0x1120

Watchdog predefined time in [ms] (Default: 1000)

0x1121

Watchdog Reset Register

0x1122

type of Watchdogs

1bin

telegram watchdog (default)

0bin

write telegram watchdog

0x4000
0x40FF*

Flag area (%MB..)*

* only for Controller (BC7300, BC8x50, IL230x-C730)

Watchdog

The watchdog is active under the factory settings. After the first write telegram the watchdog timer is initiated, and is triggered each time a telegram is received from this device. Other devices have no effect on the watchdog. A second approach, which represents a more sensitive condition for the watchdog, is for the watchdog only to be re-triggered after each write telegram. To do this, write a zero into register 0x1122 (default value "1").
The watchdog can be deactivated by writing a zero to offset 0x1120. The watchdog register can only be written if the watchdog is not active. The data in this register is retained.

Watchdog register

If the watchdog timer on your slave has elapsed it can be reset by writing twice to register 0x1121. The following must be written to the register: 0xBECF 0xAFFE. This can be done either with function 6 or with function 16.

The Bus Coupler's status register

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

FB

-

-

-

-

-

-

-

-

-

-

-

-

-

CNF

KB

FB: Fieldbus error, Watchdog timed out
KB: Bus terminal error/IP-Link error
CNF: Bus Coupler Configuration error

Key

Bit

Name

Value

Description

15

FB

1bin

Fieldbus error, watchdog time elapsed

14...2

-

-

reserved

1

CNF

1bin

Bus Coupler configuration error

0

KB

1bin

Bus Terminal error

2 byte PLC interface*

Registers in the complex terminals and Bus Terminal Controller registers can be both read and written using the 2 byte PLC interface. The complex terminal registers are described in the associated terminal documentation. The Bus Coupler registers can be used, for example, to read terminal bus diagnostics data, the terminal composition or the cycle times, and the programmed configuration can be written. It is also possible for a manual terminal bus reset to be carried out. The 2-byte PLC interface requires two bytes each of input and output data; a special protocol is processed via these 2 bytes. A description of the 2 byte PLC interface, the registers available in the Bus Couplers and of function blocks for various PLC systems that support the 2 byte PLC interface can be supplied on request.

* is not implemented in the BC8150

2 byte diagnostic interface

The terminals' error messages can be sent over the 2-byte diagnostic interface. Terminal bus diagnostics must however be activated for this purpose. The 2-byte diagnostic interface occupies two bytes each of output and input data. A special protocol is processed via these two bytes. A description of the 2 byte-diagnostic interface can be supplied on request.