Quatech INTERBUS S manual Interbus S / Configuration

5 Configuration of the fieldbus node in the master

5.1 Identification Code

In the ID cycle which is carried out for the initialization of the Interbus system, the users connected users are identified by their function and their byte length. The Interbus S coupler identifies its length after being started in the initialization phase of the bus modules and forms a corresponding ID code. To this effect each slave has an implemented identification register (ID register) comprising 2 bytes.

A 2 byte wide data unit is called a word. It enables the encoding of 65536 different states. In Interbus S, different types of users and data widths are called for the coding. This enables the master to find out what type the device belongs to, which means for

example, recognizing either frequency inverters or I/O units, like the

:$*2Ç,￿2Ç6<67(0￿ In Interbus S the manufacturers of device types are not recognized. The structure of the ID code is explained below as well as the significance of the individual bits of the ID code.

The length information can be coded from 0 to 32 words:

15

14

13

12

11

10

9

8

7

6

5

4

3

2

1

0

messages

data width

class of user

type of user

data direction I, O, I/O

Table 2: Structure of the Interbus ID code

-In the ID registers, the device group is coded in the lowest value (LSB) 8 bits (ID 0 to 7).

-In the following 5 bits (ID 8 to 12), the data width is coded. The 3 bits with the highest value (MSB) (ID 13 to 15) are used for management functions. Via these bits, dynamic fault messages are transferred during operation. These bits are not defined by the hardware.

INTERBUS S / Configuration 13

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