Siemens SIMATIC FM 353 Manual page 241

Retentive storage of parameter data
Please note the following when using the function "Write parameters with retentive
storage" (byte 4, job type 4):
Retentive writing must only occur on demand (not cyclically)!
Retentive data are stored on FEPROM (maintenance-free, no battery required).
This memory has a physical limit for the possible number of delete/reprogram
cycles: minimum 10
cycles can be multiplied, from the user's viewpoint, by providing a larger retentive
memory capacity (much larger than the parameter data memory) and organizing
the memory accordingly.
Number of delete/
reprogram cycles
Block sizes:
DB machine data
DB increments
DB tool offset data
DB traversing programs
Example:
Assuming a service life of 10 years and 24-hour operation, a typical limit = 10
Parameteriza-
tion data
MD
Traversing pro-
grams (20
blocks)
Note
SDB w 1 000 (system data block, created for module replacement), contains pa-
rameter data which were valid at the time of start-up. If data/parameters are modi-
fied during operation and stored retentively on the FM, these data are not con-
tained in SDB w 1 000. These modifications are lost when the module is replaced,
and should be traceable in the user program.
FM 353 Stepper Drive Positioning Module
6ES7 353-1AH01-8BG0
5 6
, typically 10 . The possible number of delete/reprogram
64 000
10
=
Block size (in bytes), in which param-
eter data are modified
284 bytes
468 bytes
308 bytes
108 + (20 x no. of traversing blocks) bytes
DB size Number of possible delete/
reprogram cycles
6
284 by- 237.04
10
tes
6
508 by- 125.49
10
tes
Description of Functions
6
(typical)
Number of possible delete/
reprogram cycles per min-
46
24
6
.
ute
9-41