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Rockwell Automation Publication 5069-UM003B-EN-P - January 2020
Chapter 3
Compact 5000 I/O Serial Module Features
Store and Forward
The Store and Forward Table occupies a 16-word binary data table tag
Local:x:O1.DF1RadioModem.StoreAndForward. Each bit in this file
corresponds to a DF1 Radio Modem node address. To configure a 5069-SERIAL
to Store and Forward message packets between two other nodes, the bits
corresponding to the addresses of those other two nodes must be set. For
instance, if node 2 is used to Store and Forward message packets between nodes 1
and 3, then both bits Bx/1 and Bx/3 would have to be set in the Store and
Forward Table (
). You can set bit 255 to enable Store and Forward of
broadcast packets, as well.
Figure 21 - Store and Forward in DF1 Radio Modem Protocol
Note 1—
The link layer of Node 1 blocks the retransmission of a packet
that is received with the SRC byte equal to the receiving node’s station
add retransmitted.
Note 2—
To prevent Node 2 from retransmitting a duplicate packet, the
link layer of Node 2 updates the duplicate packet table with the last 20
packets received.
Note 3—
The link layer of Node 4 blocks the retransmission of a packet
that is received with the SRC byte equal to the receiving node’s station
add retransmitted.
Note 4—
To prevent Node 3 from retransmitting a duplicate packet, the
link layer of Node 3 updates the duplicate packet table with the last 20
packets received.
Node 1
(2nd Re broadcast)
REPLY 1
Note1
Node 3
Node 4
CMD1
(1st Re broadcast)
No Bits
1, 3 ,4
1, 2 ,4
CMD1
(2nd Re broadcast)
(1st Re broadcast)
REPLY 1
No Bits
CMD1
(DST = 4, SRC = 1)
REPLY 1
(DST = 1, SRC = 4)
Note2
Note3
Note 4
Node 2