Application Of The Function Block - Siemens SIMATIC S5 Manual

Application of the Function Block

5 Application of the Function Block
To control the temperature controller by means of the function block, at least three data blocks are
required. The number of the first data block (DB-A) is specified in the parameter DBNR; for the other
two data blocks (DB-B and DB-C) the numbers are entered in the data words DW12 and DW13 of
the data block DB-A.
Function block FB 162 allows the set controller parameters to be read from the module. The
controller parameters can either be transferred to the data blocks DB-A and DB-C described above,
or to two further data blocks DB-A' and DB-C'.
The numbers and DB type of data block DB-A' and DB-C' are entered in data word DW 7 (DB-A)
or DW 8 (DB-C') and can be selected freely.
The setting of data byte DR 6 in data block DB-A decides the pair of blocks to which the values are
transferred. If parameter DBNR is assigned KY = 0,0 (indirect parameter assignment), the number
and DB type of the first data block (DB-A) must be entered in data word DW 4.
In this case, the data block DB-A must be opened before the function block is called.
The data blocks must be set up with the following lengths before the function block is called:
DB-A:
DB-B:
DB-C:
To assign parameters to the module, the controller parameters must be entered in messages 0 to
15 and 30 to 42 before the function block is called.
The entry of values marked (ST) can be omitted if the controller self-tuning function is active.
The assignments in the individual messages can be found in the Programming Instructions in Part 3
of this manual (C79000-B8576-C860).
5–48
up to DW255 DB-A': up to DW223
up to DW203 DB-C': up to DW223
up to DW223
IP244
C79000–B8576–C861–02