4.6.4.11 SF_FLASH_READ
Reading of user data from the Flash memory
The function block reads a data set from a data segment in the Flash memory and stores this data set begin-
ning at the starting flag defined at input SM. The data contained in the data set were previously stored to the
Flash memory using the SF_FLASH_WRITE function block.
NOTICE!
Access to the Flash memory is only possible using the function blocks SF_FLASH_WRITE,
SF_FLASH_DEL and SF_FLASH_READ.
NB blocks are read starting at block BNR within segment SEG and stored starting at address SM.
32 binary data or 16 word data or 8 double word data are read per block.
One block contains 38 bytes:
– 32 bytes of data
– 4 bytes for CRC checksum
– 1 byte as "written" identifier
– 1 byte for alignment
(see figure at the end of this block description)
Reading a data set is triggered once by a FALSE/TRUE edge at input EN. If no error occurred while
reading the data, output DONE is set to TRUE and the outputs ERR and ERNO are set to FALSE. The
data set is stored beginning at the defined start flag SM.
Storing the data set can take several PLC cycles.
If an error occurs during reading, DONE and ERR are set to TRUE and data from SM are equal to 0.
The error type is indicated at output ERNO.
Table 25: FB Name: SF_FLASH_READ
Name Data Type Initial Value Description, Parameter Values
VAR_INPUT
EN BOOL FALSE Activation of the FB using a positive edge
The following applies:
n EN = FALSE/TRUE edge: Reading the data
set is carried out once.
n EN = TRUE: The function block is not pro-
cessed, i.e. it does not change its outputs
anymore.
Configuration and programming
AC500-S Libraries > SafetyExt_AC500_V22.lib
30.03.2017 AC500-S 249
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