Siemens SINAMICS S120 Installation And Start-Up Manual page 78

Communication via PROFIBUS
General information about PROFIBUS
PROFIBUS telegram for cyclic data transmission and acyclic services
To transmit process data in cyclic mode and carry out acyclic services, telegrams
with the following structure are used:
Protocol
frame
(header)
Fig. 4-1
Each drive unit uses one telegram to send and receive all the process data and
carry out all the acyclic services under a single PROFIBUS address. The acyclic
data is transferred in parallel with the cyclic data, although it has a lower priority.
The overall length of the telegram increases with the number of drive objects.
Sequence of drive objects in the telegram
The following drive objects can exchange process data:
Components
1. Active Line Module
2. Basic Line Module
3. Motor Module
4. Motor Module
5. Terminal Module 31
6. Terminal Board 30
7. Control unit
On the drive side, the sequence of drive objects in the telegram is displayed via a
list in p0978[0...15] where it can also be changed.
You can use the STARTER commissioning tool to display the sequence of drive
objects for a commissioned drive system in online mode by choosing –> "Drive
unit" –> "Configuration".
When you create the configuration on the master side (e.g. HWConfig), the pro-
cess-data-capable drive objects for the application are added to the telegram in
this sequence.
4-78
Drive Drive
object 1 object 2
Process Process
data data
PZD PZD
Telegram structure for data transmission
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
Drive
object n
Process
Acyclic
data
services
PZD
Drive objects
A_INF
B_INF
SERVO
VECTOR
TM31
TB30
CU
E Siemens AG, 2004. All rights reserved
Protocol
frame
(trailer)
profibus_telegramm.vsd