1099
File Memory Instructions Section 3-26
EM File Memory-related Words and Bits
3-26-2 READ DATA FILE: FREAD(700)
Purpose Reads the specified data or amount of data from the specified data file in file
memory to the specified data area in the CPU Unit.
Ladder Symbol
Variations
Applicable Program Areas
Operands C: Control Word
As shown in the following diagram, the first digit indicates whether the source
Accessing File Flag A34314 ON when file data is actually being accessed.
Use this flag as an execution condition to pre-
vent a file memory instruction from being exe-
cuted while another is in progress.
Number of Data to
Tran sfer
A346 to
A347
The contents of these words indicate the sta-
tus of data file transfers.
When an FREAD(700) or FWRIT(701) instruc-
tion is executed, the number of words or fields
to be transferred is written to these words. The
value is decremented by 1 as each word or
field is transferred.
A346 contains the rightmost 16 bits and A347
contains the leftmost 16 bits of the 32-bit
binary value.
Name Address Operation
EM File Memory For-
mat Error Flag
A34306 ON when there is a format error in the starting
bank of EM file memory.
EM File Format Starting
Bank
A344 Contains the starting bank number of the EM
Area that has been formatted for use as EM
file memory. Contains FFFF when none of the
EM Area has been formatted.
To convert the EM Area for use as file memory,
the PLC Setup’s EM File Memory setting must
be set to 1 and the EM File Memory Starting
Bank (0 to C) must be set. All EM banks from
the starting bank to the last bank will then be
formatted for use as file memory.
Name Address Operation
FREAD(700)
C
S1
S2
D
C: Control word
S1: Number of words and
First source word
S2: Filename
D: First destination word
Variations Executed Each Cycle for ON Condition FREAD(700)
Executed Once for Upward Differentiation @FREAD(700)
Executed Once for Downward Differentiation Not supported.
Immediate Refreshing Specification Not supported.
Block program areas Step program areas Subroutines Interrupt tasks
OK OK OK OK
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