Show/Hide Toolbars

PROFIBUS Manual

Navigation: MS0: cyclic data

Address changes

Scroll Prev Top Next More

Before commissioning a PROFIBUS system, stations must be assigned unique addresses.

 

The PROFIBUS address of a DP slave can be adjusted in two ways:

1.Through settings on the device with the help of switches or another control interface.

2.By sending a special telegram via the PROFIBUS. Address 126 is reserved as the default address for a DP slave.

 

This second function is not necessarily supported by every DP slave. The entry

 

Set_Slave_Add_supp = 1

 

in the GSD file indicates whether this function is supported.

 

The address of a DP slave can only be changed in the state Wait Parameter (WPRM). Only when the DP slave is in this state can the master (typically a class 2 master) send a telegram to modify the DP slave's address. The master should first verify that the new address is actually free.

 

After the address has been changed, it is necessary to execute a cold-start (power supply off and on again) of the DP slave.

 

Address: telegram to change address with 4 bytes

New address

Ident number

High byte

Ident number

Low byte

Extensions

 

 

7

6

5

4

3

2

1

0

Address byte 1: New address

0–125

(0x00–0xFE)

New address

 

7

6

5

4

3

2

1

0

Address byte 2 & 3: ident number

0-255

(0x00-0xFF)

Ident number high byte

0-255

(0x00-0xFF)

Ident number low byte

 

7

6

5

4

3

2

1

0

Address byte 4:

 

 

 

 

 

 

 

X

Further changes of the address are not allowed

0

0

0

0

0

0

0

 

Reserved