KB81707
Published: January 6, 2012
Revision: 1.0

Cannot connect with Listen and Accept Incoming Communication commands


Applies To:

SNAP-PAC-S1
SNAP-PAC-S2
SNAP-PAC-S1-W
SNAP-PAC-S2-W
SNAP-PAC-R1
SNAP-PAC-R2
SNAP-PAC-R1-W
SNAP-PAC-R2-W

Versions Affected:

Problem was discovered in version: R9.1d


Symptoms:

'Error -441, No listening on socket' may be returned when listening for peer communication in a PAC Control strategy. An example of this type of TCP/IP communication is shown in the example on page 255 of the PAC Control User's Guide (form 1700, revision 111014).

The commands Listen for Incoming Communication and Accept Incoming Communication are used to establish the TCP/IP communication. The Accept Incoming Communication command is called repeatedly, with no connection ever established.


Workaround:

If error -441 is returned when the Accept Incoming Communication command is executed, change the strategy to loop back to the block with the Listen for Incoming Communciation command and add a 100 ms delay after the Listen for Incoming Communication command.


Questions?

Contact: Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
Email: support@opto22.com


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