PROFIBUS Communication
3/13
WL Circuit Breaker
Control Bytes
The three basic types differ with
regard to the quantity and content
of the data reported from the circuit
breaker to the class 1 master (e.g.
PLC) with each Data_Exchange.
By standard convention, this data
refers to input data from the point
of view of the PLC.
The output data of the class 1 master
is identical in all three basic types. The
control bytes to the circuit breaker are
always two bytes long. These control
bytes can be used to switch the circuit
breaker (open/close), acknowledge
trips, and reset memory contents.
It is sufficient to set the bits for all
the controllers to between 0.5 and
5 seconds because setting the output
is edge triggered. The control bits
must then be reset to prevent any
unwanted actions from subsequently
being triggered.
PROFIBUS Write Protection
(DPWriteEnable)
Important write accesses can be
blocked from the PROFIBUS-DP.
For this purpose, a hardware input
is available on the COM15 module.
If this input is not bridged (active
release), write access is not possible,
with noted exceptions for remote
diagnostics. For additional
information on the precise
assignment of the write protection
inputs (DPWriteEnable), reference
Chapter 2.
The following actions are blocked if
the input of the write protection
function has not been bridged:
•
Open /Close
• Reset the current trip
• Change the protection parameters
• Change the parameters for the
extended protection function
(metering function)
• Change the communication
parameters
• Change the parameters for the
measured value setting (metering
function)
• Reset maintenance information
(counters)
Byte n
Byte n+1
Control bytes to the circuit breaker
Byte
Bit
WL
Switch circuit breaker
0 = Not defined (no action)
0/1
1 = Switch off (open the main contacts)
2 = Switch on (close the main contacts)
3 = Not defined (no action)
2
A current trip is acknowledged and reset
3
Not used
4
Activate the free user output on the COM15 module
5
Not used
6
Not used
7
Not used
0/1
Not used
2
Delete trip and event log
3
Reset all min./max. value memories
(except temperature)
4
Reset min./max. temperatures
5
Not used
6
Reset all resettable maintenance information
and counters
7
Bit for synchronizing the system time to the current
half hour
Table
3-9
All three basic types contain a 2-byte block featuring the most important binary
information transmitted with the message for controlling the circuit breaker
WL PROFIBUS Communication and Electronic Accessories • July 2004
