Mitsubishi MELSEC-F User Manual page 147

7 FIXED BUFFER COMMUNICATION (WITH THE NO PROCEDURE
CONTROL METHOD)
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1) Upon receiving data from the designated external device (set in the
open processing), the Ethernet module processes the following.
• Stores the received data to the fixed buffer (No. 2) area.
(Area beginning from the head address of the target fixed buffer + 1)
• Stores the data length to the head address area of the target fixed
address ( 1)
• Fixed buffer communication receive results (BFM#1611)
• Fixed buffer receive status signal (BFM#20485 b1)
1 The received data length is expressed by a byte count.
When an odd number of data bytes is received, the last byte of
received data is stored at the lower byte of the last data storage
area. (The higher byte becomes a non-constant value.)
2) Execute the FROM instruction to read out the receive data length and
receive data to the PLC.
3) Execute the TO instruction to write "0002H" in the fixed buffer
communication receive results (BFM#1611).
4) Result of the receiving processing is indicated.
POINT
(1) The destination setting (see Section 5.5) for a connection whose parameters
are set in FX Configurator-EN (GX Developer) becomes valid when the open
completion signal (BFM#20480 ... corresponding bit) of the Ethernet module
switches from off to on.
(2) When data is received and the data in the buffer memory's fixed buffer is set,
BFM #1610 to 1617 is set to "0001H".
(3) At abnormal data receiving, each buffer memory status becomes as follows.
• Fixed buffer receive completion signal (BFM#20485 b1) remains off.
• Fixed buffer communication receive results (BFM#1611): 0008
• Data is not stored in the fixed buffer (No.2) area.
MELSEC-F
: 0001
H
: ON
H
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