Communication-capable Circuit Breakers
The write-protect function ensures that all the
required information can be transmitted, but
prevents any changes to the status of the circuit
breaker. Changes can then only be made locally.
Why does the write protection function permit
certain actions?
All actions that are not blocked are for remote
analysis only and do not have any effect on the
current status.
Data Exchange via the COM15 Module
When the COM15 module is configured to
exchange data, it is important to note that it
is shipped as standard with PROFIBUS address
126. This can be changed during system
configuration (e.g. with the BDA or ETU776
display).
The COM15 module has two LEDs (PROFIBUS
and
Cubicle
BUS
) for diagnostic purposes.
These indicate the operating status of the
communication line and the
Cubicle
BUS
networks.
Two LEDs are used to determine whether a
Cubicle
BUS
module in the circuit breaker is
operational. First, the “COMM” LED on the trip
unit must be green, that is, the trip unit has
recognized at least one other
Cubicle
BUS
module.
At a minimum, this would only be the Metering
Function/Metering Function
PLUS
if the
Cubicle
BUS
was then interrupted. Second, the
Cubicle
BUS
LED on the COM15 module must be taken into
account. If this is lit with a steady green light, a
connection exists from the COM15 module to at
least the metering function/metering function
Plus
module.
If both LEDs are green (steady light for
Cubicle
BUS
on the COM15 module and COMM on the trip
unit), communication is fully established between
the trip unit and the COM15 module.
Data is exchanged according to the following
principle: an up-to-date copy of all WL Circuit
Breaker data (apart from the waveform buffer) is
always stored in the COM15 module. A response
to a data query from the COM15 module to the
supervisory system can, be typically transmitted
in just a few milliseconds. Write data from the
supervisory system is forwarded to the
appropriate addressee on the
Cubicle
BUS
.
2/10
WL Circuit Breaker
Graphic
2-2
Rear view of the COM15 module. The RJ45 connection for the external
Cubicle
BUS
modules can be clearly seen here. If no external
Cubicle
BUS
module
is connected, the bus must be terminated with the terminating resistor.
Table 2-3
The 4 black cables from the COM15 module must be connected to
terminal strip X7, which is used to connect the COM15 module to the modules on
the
Cubicle
BUS
in the circuit breaker.
Meaning
Position and text on the cable
Cubicle
BUS
-
X7.1
Cubicle
BUS
+
X7.2
24V DC +
X7.3
24V DC ground
X7.4
Figure
2-1
Front view of the PROFIBUS module for the WL Circuit Breaker with the
PROFIBUS connection and the two LEDs. The figure below shows a section
of the ETU745 and its LEDs for displaying status.
WL PROFIBUS Communication and Electronic Accessories • July 2004
