ABB AC500-S Safety User Manual page 311

4.6.7.12 SF_FLASH_WRITE
Writing of user data to the flash memory
The function block writes a data set to a data segment in the flash memory. For that purpose,
two data segments are available in the safety CPU. The delete operation (function block
SF_FLASH_DEL) always deletes a data segment as a whole. One data segment consists of
1724 blocks (0 ... 1723). Each block comprises 38 bytes. The maximum number of writing
cycles to the flash memory is limited. Deleting data in the flash memory is also considered to be
a "writing" cycle.
After a delete operation, data can be written only once to each of these 1724 data segment
blocks. If a block containing data is to be overwritten with new data, the entire data segment has
to be deleted first. In doing so, all data in this segment will be lost.
NB blocks are read starting at address SM and stored in segment SEG starting at block BNR.
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
Ä Table 88 "Structure of one of the flash memory segments with user data" on page 310
Once the write operation for a data set has been started (by a FALSE/TRUE edge at input EN),
the data contained in the data set must not be changed anymore until the write operation com-
pletes (DONE = TRUE). Storing the data set in the flash memory can take several safety CPU
cycles.
With a FALSE/TRUE edge at input EN, the data set is written once. Input EN is not evaluated
again until the storage procedure is finished (DONE = TRUE).
After the write operation is finished, the function block outputs DONE, ERR and ERNO are
updated. Data storage was successful if DONE = TRUE and ERR = FALSE. If DONE = TRUE
and ERR = TRUE, an error occurred. The error type is indicated at output ERNO.
A new FALSE/TRUE edge at input EN starts a new write operation. Input BNR must point to the
next free block for the next write operation since no new data can be written to blocks that
already contain data without a preceding deletion of the data segment.
Table 89: FB name: SF_FLASH_WRITE
Name Data type
VAR_INPUT
EN BOOL
2020/06/19
Initial value Description, parameter values
FALSE Activation of the FB using a positive edge
The following applies:
● EN = FALSE/TRUE edge: Reading the data set is
carried out once.
● EN = TRUE: The function block is not processed,
i.e. it does not change its outputs anymore.
3ADR025091M0208, 12, en_US
Configuration and programming
AC500-S libraries > SafetyExt_AC500_V22.lib
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