DRA-2 UNIVERSAL COMMUNICATION NODE
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USER GUIDE - Rev.5 (January 2018)
5.3.3
PLC
This submenu appears when the equipment has PLC interfaces. It allows the operating
parameters of the equipment PLC ports to be configured, whose connectors are identified
as
PLC 1 and PLC 2.
The operating paradigm of the PLC interfaces is the
Master-Slave
type, but even so the
communication is restricted to end-to-end topologies, since one
Master
admits multiple
Slaves. On the other hand, the possibility of several PLC communications existing is
envisaged, either through sharing one environment or acting as interferent signals.
The mechanism for guaranteeing exclusion between several PLC communications is the
use of different codes for each one, which are also used for encrypting data, thereby
guaranteeing privacy. This identification code is called
Network Management Key (NMK)
and is shared by all the equipment in one group. Each NMK is made up of a sequence of
16 bytes.
Each of the PLC interfaces must have an NMK assigned to it and in normal conditions,
different from each other. In all cases, special configurations are foreseen for the interfaces,
so that they can operate without the user having to configure them a priori. For instance, it
is possible to have a basic configuration for the equipment, even without knowing its exact
location.
These specific modes lead to the presence of configuration parameters in addition to the
NMK which are
NMKs group (GNMK)
and
Operation mode
.
Each of the 10 GNMK available includes multiple NMKs. The equipment is able to travel in
cycles through the GNMK assigned to an interface until it detects the establishing of a
successful connection (
AUTO
mode). It can also act like the end that accepts the
connections (
ASK
mode), in which case the NMK is obtained by consulting a server which
controls them, that can be enabled in the equipment itself.
The PLC interfaces in
AUTO
mode always try to establish connection with the last
successful NMK value.
Only one
GNMK server
must be enabled for all the equipment operating in the
same
GNMK group.
