Operations Of The "Reception Done Copy" Flag And Multiplex Reception - Panasonic AF7CPS Series User Manual

6.3.4 Operations of the "Reception done copy" flag and multiplex reception

 Operation and function of the "reception done copy" flag (X4)
 The "reception done copy" flag (X4) turns ON when the GPRECV instruction is executed and
data are copied from the reception buffer to the specified operation memory, and turns OFF
when the END instruction is executed.
 Processing in the case of multiplex reception
 If the time from the reception of data in the reception buffer to the subsequent data reception
is shorter than the PLC scan time, and the receiving frequency is high, it is possible that the
reception done flag (X0) remains ON and cannot detect sequential receptions.
 In cases where it is necessary to process sequentially received data, constantly execute the
GPRECV instruction, in combination with the "reception done copy" flag (X4).
 Referring to the "reception done copy" flag (X4), you can confirm whether there are lately
received data.
Reception
buffer data
Reception
done flag
(X0)
Execute
GPRECV
instruction
Reception done
copy flag
(X4)
1 scan time
C
C
R R
After always executing GPRECV instruction, confirm
whether there are lately received data referring to the
reception done copy flag (X4).
6.3 Receiving Operation
In the case of sequential receptions, the
reception done flag (X0) remains ON.
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