Open Processing/Close Processing Of The Connection - Mitsubishi MELSEC-F User Manual

5 COMMUNICATION PROCEDURE

5.6 Open Processing/Close Processing of the Connection

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This section explains the open processing/close processing using sequence programs.
(1) Open processing
(a) The purpose of the open processing is to establish a connection with an
external device in order to perform the following forms of data
communication.
They can all be performed with an external device opened by the user.
• Communication using MC protocol
• Sending/receiving using the fixed buffers (Procedure exists)
(b) When the following is set by the parameter settings, the open processing
should be performed in a sequence program.
1) In the Operational settings (Section 4.6)
When "Do not wait for OPEN" is set in the "Initial timing setting".
2) In the open settings (Section 5.5)
When "Active" is set in the "OPEN system" setting.
(c) In order to perform open processing, the initial processing must be complete
(BFM #28b0: ON) and the hub communication status (BFM #28b7: ON)
must be on.
(d) A connection with an external device must be established (open processing)
when communicating using either the MC protocol, fixed buffers. ( 1)
Two types of data communication mentioned above can also be performed
with an external device opened by the user.
1 Since the Ethernet module recognizes the external device by the IP
address, the open processing is required for UDP communication.
(e) Up to a maximum of 8 connections can be opened to external devices.
However, two buffers are required when communicating with the same
external device using fixed buffer communication, so in this case the
number of external devices that can be communicated with will be lower.
POINT
During communication using MC protocol, if data communication is to continue
even after the Ethernet module installed PLC, has been placed in the STOP status,
enable "Always wait for OPEN (communication possible at STOP time)" under
"Initial timing setting" (see 4.6, "Operation Settings").
MELSEC-F
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