Omron SYSMAC CP Series, Руководство пользователя

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15-37
15 Ethernet
CP2E CPU Unit Software User’s Manual(W614)
15-5 Soc
ket Ser
vic
es
15
15-5-
3
Soc
k
et Ser
v
ices a
nd Soc
k
et Status
Precautions for Correct Use Precautions for Correct Use
A Socket Service Parameter Area cannot be used for other sockets once open processing has
been successfully completed for it. Check the socket status before attempting to open a socket.
TCP socket status is provided in words m+4 to m+6 in the DM Area for sockets 1 to
3 .
When a send or receive request is made, the data will be automatically sent or received accord-
ing to the send/receive data address in the Socket Service Parameter Area. When processing
has been completed, a response code will be automatically stored in the Socket Service Param-
eters.
When using socket services, it is important to consider the timing of the status changes in the Socket
Status Area. The diagram below shows a flowchart for opening UDP. The flow is similar for other socket
services. Replace the names of the appropriate flags in the flowchart to adapt it to other socket ser-
vices.
Note For details about timing charts, refer to SECTION 6 Socket Service s in the Ethernet Unit s Con s truction of
Application s Operation Manual (Cat. No. W421).
Socket services cannot support CMND command.
15-5-3 Socket Services and Socket Status
Check TCP Connection/UDP Open Flag. The specified UDP socket is
already open.
T u rn O N UDP Open Re qu est S w itch.
Start UDP Open.
OFF?
Program Flow
Is Bit 15 (Open Flag) in the socket stat u s w ord for
the socket b eing u sed OFF?
(Checks to see if the socket is open b efore com-
m u nications and close processing.)
YES
Error Evaluation
UDP socket opened.
N O
This Socket Ser v ice Re qu est S w itch is u sed to re qu est
opening of a UDP socket to the Ethernet Unit.
Confirm end of processing.
0000?
YES
N O
O N /OFF?
OFF
This Socket Ser v ice Re qu est S w itch that w as t u rned
O N w ill b e t u rned OFF b y the Ethernet Unit w hen
processing has b een completed.
Check response code.
Is the response code 0000, indicating a normal end?
An error occ u rred. The specified
socket co u ld not b e opened.