Parameters Common To The Ouc Library Instructions - Siemens SIMATIC S7 System Manual

9.4.1

Parameters common to the OUC library instructions

The following parameters are common to the OUC library instructions:
● EN: You set the EN input to TRUE to call the instruction. You must set the EN input to
TRUE until the instruction completes (until either Done or Error is set). The CPU only
updates the outputs when your program sets EN and calls the instruction.
● Req: You use the Req (Request) input to initiate the operation. The Req input bit is level-
triggered. You should connect the Req input to the library instruction with a positive edge
instruction so that the action is initiated only one time. The program ignores the Req input
while the instruction is Busy.
● Active: The Active input commands the connect instructions whether to create an active
client connection (Active = TRUE) or a passive server connection (Active = FALSE). An
active connection is one in which the local CPU initiates communications to the remote
device. A passive connection is one in which the local CPU waits for the remote device to
initiate communications.
The S7-200 SMART CPUs support eight active connections and eight passive
connections for Open User Communication. UDP connections are counted as passive
connections since there is no active communication establishment.
● Done: The OUC instruction sets the Done output when the operation is complete and
there are no errors. If the instruction sets the Done output, Busy, Error, and Status
outputs are zero. Other outputs (for example, the number of received bytes) are valid only
when the Done output is set.
● Busy: The Busy output indicates that the operation is in progress. The OUC instruction
sets the Busy output when you initiate an operation with Req set to TRUE. The Busy
output remains set for all subsequent calls to the instruction until the operation is
complete.
● Error: The Error output indicates that the operation completed with an error. If the OUC
instruction sets the Error output, then the Done and Busy outputs are set to FALSE. If the
OUC instruction sets the Error output, the Status output indicates the reason for the error.
All other outputs are not valid if the Error output is set.
● ConnID: The ConnID number is the identifier for the connection. You establish the
ConnID when you create the connection with TCP_CONNECT, ISO_CONNECT, or
UDP_CONNECT. You can pick any value in the range 0 to 65534 for the ConnID. Each
connection must have a unique ConnID. The program uses the ConnID to specify the
desired connection for subsequent send, receive, and disconnect operations.
S7-200 SMART
System Manual, V2.3, 07/2017, A5E03822230-AF
9.4 Open user communication library
Libraries
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