Communications Capabilities
S5-115F Manual
Coordination bytes
Coordination bytes form the interface to the PLC operating system. The programs of the slaves use
these bytes to track and influence the flow of LAN traffic. The positions of the coordination bytes
are configured using COM 115F.
Figure 7-4 explains the individual bits.
2
7
2
4
2
2
2
1
2
0
Error
0: No error
1: Error during last data transfer
Slave OFF
0: No slave off
1: At least one slave off
LAN RUN
0: LAN is in STOP mode
1: LAN is in RUN mode
Information from the bus master
REC-PERM
0: The program can fetch data from the Receive mailbox. The operating system has no access.
1: The operating system can accept data in the Receive mailbox from the LAN. The program has no access.
If REC-PERM = ”1”, the operating system fills the Receive mailbox with data. The operating system then
resets REC-PERM to ”0” (=0).
”Receive” Coordination Byte (CBR)
2
0
2
4
2
7
Error during last data transfer
0: No error
1: Error detected
Information for the bus master
”Send” Coordination Byte (CBS)
SEND-PERM
0: The program can process the Send mailbox. The operating system has no access.
1: The Send mailbox is enabled to transmit on the LAN. The program has no access.
SEND-PERM =”1” causes the operating system to transmit the contents of the Send mailbox. The operating
system then resets the SEND-PERM bit to ”0”.
Figure 7-4. Structure of the ”Receive” and ”Send” Coordination Bytes
7-6
EWA 4NEB 811 6148-02