Dat
e of
I
s
sue
04/
22/
2008
Par
t No.
194341
Optical data coupler LS611
Special notes on the use of several masters
22
Illustration 8.3
Light beam interruption in multi-master systems
8.2
Collision prevention
If it is not possible to arrange the topology of the field bus structure in such a way that all
masters are located in one segment (no optical data coupler in-between), LS611 pro-
vides the possibility to switch one function on on the stationary side of the optical data
coupler pair, which prevents the collision caused by the Class2-Master in the star seg-
ment.
This function is referred to as "C1CP", meaning Class1-Master Collision Protection.
Some hand-held terminals or touch panels provide the option to have
this PROFIBUS station communicate with the Class1
-
Master as a pas-
sive station or slave. But, this does not solve the problem by any
means. This communication relationship is used exclusively to ensure a
faster cyclical access. The stations behave like masters in this configu-
ration as well.
LS611
LS611
LS611
LS611
LS611
LS611
Stationary
Mobile
Class 1 - Master
PLC
Class 2 - Master
Slaves ...
Class 2 - Master
Slaves ...
Class 2 - Master
Slaves ...
Slaves
