Communication via PROFIBUS
General information about PROFIBUS
4-78
E Siemens AG, 2004. All rights reserved
SINAMICS S120 Installation and Start-Up Manual, 12/04 Edition
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:
profibus_telegramm.vsd
Protocol
frame
(header)
Process
data
PZD
Drive
object 1
Process
data
PZD
Drive
object 2
Process
data
PZD
Drive
object n
Protocol
frame
(trailer)
Acyclic
services
Fig. 4-1 Telegram structure for data transmission
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 Drive objects
1. Active Line Module A_INF
2. Basic Line Module B_INF
3. Motor Module SERVO
4. Motor Module VECTOR
5. Terminal Module 31 TM31
6. Terminal Board 30 TB30
7. Control unit CU
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.
To Next Page
Loading...
Need help?
General