Filter
Top Products
Application and Function
33003405 07/2007 29
Cable
Disconnection
In a Safety PLC network, areas are covered using the Safety network. Therefore,
damage or disconnection of the communications cable may occur. In the system
below, the "X" represents a cable break between Safety PLC 2 and Safety PLC 3.
The communications between each of the systems will cease. As a result, the
following will occur:
l if the Safety PLC 2 system was dependent on the inputs of the Safety PLC 3
system, the corresponding outputs will automatically be set to "zero",
l if the Safety PLC 3 system was dependent on the inputs of the Safety PLC 2
system, the corresponding outputs will automatically be set to "zero", and
l if the systems are still provided with the 24 VDC power supply, the two systems
will continue to operate the remaining inputs and outputs of each separate
system.
The following diagram shows an example of the Safety PLC network interruption:
If the local network is reacting only on the inputs of the same system, the PLC
system continues to run without failure.
Safety PLC Safety PLC Safety PLC
Remote I/O module
Remote I/O module
Remote I/O module
Remote I/O module
Remote I/O module