Filter
Top Products
5 - 25
MELSEC-F
COMMUNICATION PROCEDURE5
5 - 25
5.6 Open Processing/Close Processing of the Connection
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 be performed with an external device opened by the user.
• Sending/receiving using the fixed buffers (Procedure exists/No procedure)
• Communication using MC protocol (The communication by MC protocol
needs to be set by an existing procedure (MC).)
(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").