Mitsubishi MELSEC-A series, Programming Manual

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7. APPLICATION INSTRUCTIONS
7
−
61
MELSEC-A
FIFR
(1) Reads data from the first device after the pointer of FIFO table and stores the
data into the of (S).
(2) The data of data table is shifted to the front one by one and the preceding data
is set to 0. (i.e. data is lost)
(3) Subtracts 1 from the content of pointer.
(4) If the FIFR instruction is executed when the content of pointer is 0, operation
error occurs.
Execution Conditions
Operation Errors In the following case, operation error occurs and the error flag turns on.
•
(FIFO table head address) + (pointer) value exceeds the corresponding device
range when the FIFW(P) instruction is used.
•
The FIFR(P) instruction has been executed when the pointer value is 0.
OFF
ON
Executed
per scan
Executed
per scan
Executed
only once Executed
only once
Read/write command
P
Stored into device
at (S).
1 is reduced.
R10
R11
R12
0
Data table
Pointer
Movement of
data