S5-115F Manual
Communications Capabilities
Method of operation:
Both subunits always have the same contents in all Send mailboxes common to SINEC L1 LAN A
and SINEC L1 LAN B. Since the SINEC L1 LANs are not synchronized with each other, they send the
individual messages from one Send mailbox at different times. However, the time difference is, at
the most, equal to the SINEC L1 safety time. Since the Receive mailbox is available in both subunits,
it follows that both subunits have the same data in their Receive mailboxes.
If you wish to make use of the high availability or fault tolerance of the two-channel SINEC L1 LAN,
call FB 253 MBXT before you access the mailbox of LAN B. FB 253 copies the contents of the
mailbox into the mailbox of the other LAN if an error has been reported in connection with its
data traffic. If both LANs have faults, an error message results followed by STOP.
Your program must additionally evaluate the error information via the SINEC L1 LANs in Block 1 of
error DBs 2 or 3 ( Vol. 2, 5.4.2 of the manual) and issue an operator message.
Please note the following differences in initializing and configuring single and two-channel
SINEC L1 LANs compared with the ”normal” operating mode of the LAN system ( 7.2.1):
•
You must set up a Send mailbox in the source slave and a Receive mailbox in the destination
slave for both the send and receive end of every data path. There are two Receive mailboxes
and one Send mailbox per data path in each subunit for a two-channel SINEC L1 LAN and two
Send mailboxes per subunit for the master traffic.
•
Send mailboxes can also be used repeatedly if identical data is sent to different destination
slaves.
•
Data is written to, and read from, the mailboxes by the operating system or by FB 254 SYNC
with the ”SINEC L1 processing” identifier ( Vol. 2, 5.1.5 of the manual). For this reason, no
coordination is required in the user program.
•
The mailboxes need not be cleared in order to receive the next transfer. Data is written into
them regularly for safety reasons even when no change has taken place.
•
The mailboxes for interslave data traffic can accommodate messages with a maximum of 62
bytes of useful data when using message mode 115F-13 and 60 bytes when using message
modes 115F-14 or 115F-15.
•
The mailboxes for master-slave data traffic can accommodate messages with a maximum of
64 bytes.
•
Depending on the message mode configured, safety-related messages are provided with high-
level protection for the destination slave number and a change byte for message protection.
EWA 4NEB 811 6148-02
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