Logical Peer - Siemens SINUMERIK 840 Planning Manual

1 General 06.91

1.1.7 Logical peer

1.1.7 Logical peer
Logical peer is the symbolic designation for a technological function module in a system, e.g.
in the SINUMERIK 8X0.
A system can contain one or several function modules.
In the case of a bus connection, a "logical peer" is identified by the combination of transport
connection and addressing in the application layer.
One or several logical peers can be served via a TPV transport connection. (When connecting
the SINUMERIK 8X0 to the Siemens FMS only one logical peer per transport connection is
allowed.)
The "logical peer" is determined by the addressing in the application layer alone in the case of
a serial connection.
If the AS 512 protocol is used, several logical peers can be allocated to one interface.
If an interface is configured without the AS 512 protocol, only one logical peer can be allocated
to it.
In the communication process, a distinction is made between the transmitting and the receiving
logical peer.
The transmitting logical peer is the symbolic designation for the functional unit by which the
message frame was sent whereas the receiving logical peer refers symbolically to the function
module by which the message frame is to be received.
In input direction, the SINUMERIK 8X0 recognizes the sender and/or receiver by means of the
address information contained in the application part of the message frames.
In output direction, the logical peer to which the message frame is to be sent is assigned to
the corresponding connection.
The diagrams below give examples of logical peers both for a production control computer and
for an NC, first for the bus and then for the serial connection.
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SINUMERIK 840/880 (PJ)