8.1.5 FB 65 - TCON - Establishing a connection
Both communications partners call FB 65 TCON to establish the communications connec-
tion. In the parameters you specify which partner is the active communications transmis-
sion point and which is the passive one. For information on the number of possible con-
nections, please refer to the technical data for your CPU. After the connection is
established, it is automatically monitored and maintained by the CPU. If the connection is
interrupted, such as due a line break or due to the remote communications partner, the
active partner attempts to reestablish the connection. In this case, you do not have to call
FB 65 TCON again. An existing connection is terminated when FB 66 TDISCON is called
or when the CPU has gone into STOP mode. To reestablish the connection, you will have
to call FB 65 TCON again.
Both communications partner call FB 65 TCON in order to configure their local communi-
cations access point. A connection is configured between the user program and the com-
munications level of the operating system. No connection is established to the remote
partner. The local access point is used to send and receive UDP message frames.
FB 65 TCON is an asynchronously functioning FB, which means that its processing
extends over several FB calls. To start establishing a connection, call FB 65 with REQ =
1. The job status is indicated at the output parameters RET_VAL and BUSY. STATUS
corresponds to the RET_VAL output parameter of asynchronously functioning SFCs (see
also Meaning of the Parameters REQ, RET_VAL and BUSY with asynchronous SFCs).
The following table shows the relationships between BUSY, DONE and ERROR. Using
this table, you can determine the current status of FB 65 or when the establishment of the
connection is complete.
BUSY DONE ERROR Description
TRUE irrelevant irrelevant The job is being processed.
FALSE TRUE FALSE The job was completed successfully.
FALSE FALSE TRUE The job was ended with an error. The cause of the error can be found
in the STATUS parameter.
FALSE FALSE FALSE The FB was not assigned a (new) job.
Parameters
Parameter Declaration Data type Memory area Description
REQ INPUT BOOL I, Q, M, D, L Control parameter REQ, initiates establishing the
connection at rising edge.
ID INPUT WORD M, D,
constant
Reference to the connection to be established to the
remote partner or between the user program and the
communications level of the operating system. ID
must be identical to the associated parameter ID in
the local connection description. Range of values:
0001h ... 0FFFh
DONE OUTPUT BOOL I, Q, M, D, L DONE status parameter:
n 0: Job not yet started or still running.
n 1: Job executed without error.
BUSY OUTPUT BOOL I, Q, M, D, L
n BUSY = 1: Job is not yet completed.
n BUSY = 0: Job is completed.
Use with TCP native and
ISO on TCP
Use with UDP
Description
VIPA SPEED7
Network Communication
Open Communication > FB 65 - TCON - Establishing a connection
HB00 | OPL_SP7 | Operation list | en | 18-30 122
To Next Page
Loading...
