Extended instructions
9.10 Data block control
S7-1200 Programmable controller
540 System Manual, V4.2, 09/2016, A5E02486680-AK
Recipes and machine setup information
You can use the READ_DBL and WRIT_DBL instructions to manage recipes or machine
setup information. This essentially becomes another method of achieving retentive data for
values that do not change often, although you would want to limit the number of writes to
prevent wearing out the flash prematurely. This effectively allows you to increase the amount
of retentive memory beyond that supported for the normal power-down retentive data, at
least for values that do not change often. You could save recipe information or machine-
setup information from work memory to load memory using the WRIT_DBL instruction, and
you could retrieve such information from load memory into work memory using the
READ_DBL instruction.
Table 9- 222 Condition codes
0081 Warning: that the source area is smaller than the destination area. The source data is copied complete-
ly with the extra bytes in the destination area unchanged.
Call with REQ = 0: BUSY = 0
7001 First call with REQ = 1 (working): BUSY = 1
th
8081 The source area is larger than the destination area. The destination area is completely filled and the
remaining bytes of the source are ignored.
Source data block type error
Missing source data block
The source DB is being edited by another statement or a communication function.
Destination data block type error
Missing destination data block
The destination DB is being edited by another statement or a communication function.
More than 50 READ_DBL or 50 WRIT_DBL statements are currently queued for execution.
Recipes (Page 498)
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