PROFIBUS Communication
3/8
WL Circuit Breaker
PROFIBUS Profile for Circuit Breakers
The PROFIBUS User Organization
promotes the use of joint, multi-
vendor profiles for different
device classes, such as motor
starters and measuring
instruments. For low-voltage
switchgear and controlgear,
a separate profile has been
defined for circuit breakers.
The PROFIBUS User Organization
profile has been extended to
include diagnostic functions
and DPV1 enhancements.
Cyclic Data Transmission
With cyclic data transmission, a
defined quantity of user data is
transmitted with each message.
When the slave (in this case, the
WL circuit breaker) is parameterized,
the quantity of data to be transmitted
cyclically between the circuit breaker
and PLC must be defined. Cyclic data
transmission is the best method of
transferring information that is
needed quickly and on a continuous
basis. The interval between two
values depends on the number of
stations involved, the quantity of
data, and the baud rate. The quantity
of data cannot be changed during
operation. For this reason, data
transmission that is exclusively cyclic
is suitable for communication that
generally handles small volumes of
user data. Cyclic data transmission,
however, is not suitable when larger
data packages are to be transmitted,
for example, for occasional setting
and maintenance checks.
This type of transmission is only
required occasionally and should be
taken into account for each message,
because the messages would become
very long and take a long time to
transmit.
Basic Types for Cyclic Data
Transmission
Because of the large amount of
data provided by WL circuit breakers,
a compromise had to be reached
between the data volume and
performance on the PROFIBUS-DP.
If only a small amount of information
is used every time a large amount of
data is transmitted in each exchange
(Data_Exchange), the performance
of the PROFIBUS-DP can be affected.
For this reason, three base types
are available to enable efficient and
flexible data transmission. Depending
on the application, the most suitable
base type and accompanying bus
configuration can be selected during
configuration. This is carried out
using a PROFIBUS-DP configuration
tool, such as COM PROFIBUS or
HWConfig in SIMATIC S7. The base
types are pre-assigned and enable
rapid commissioning without the
need for additional configuration
or parameterization.
A user-defined configuration can also
be created within a base type using
the BDA.
Note:
Data that is not required all
the time can also be transmitted
via DPV1.
PROFIBUS User Organization Profile
The PROFIBUS-DP communication
profile for WL circuit breakers was
included in the profile for low-
voltage switchgear and control gear
(circuit breakers) by the PROFIBUS
User Organization and adopted
accordingly.
As a result, WL circuit breakers
communicate using state-of-the-
art technology.
The document can be downloaded
from the PROFIBUS User Organization
at: http://www.profibus.com
Figure 3-7
WL circuit breakers conform to
the PROFIBUS profile for circuit breakers.
WL PROFIBUS Communication and Electronic Accessories • July 2004
