ibaBM-DP
Manual
Issue 1.7
123
Slave 38 – Bus 1
•
input 122 BYTES: 772…893
•
input 122 BYTES: 894…1015
Fig 102: Address range Slave 38 - Bus 1
12.3 Transferring data to active slaves
In the PLC program of the S7-400H, you need to output the data you want to record with
the active slave always to the two slaves belonging together.
Hereafter, we give an example of how data can be written on the slaves on bus 0 and 1
in the S7-400H in the exemplary PROFIBUS configuration in chapter 12.2.2.
For this purpose, you generate in your PLC a data block (DB) for each active slave. In
this block, you cyclically write the data you want to record. You can customize the struc-
ture of the DB. The length of the DB has to equal the length of the output data range of
the active slave (i.e. again a max. of 244 Bytes).
In our example, the interface DB looks as follows:
Fig. 103: Example interface data block
The data is output by calling up SFC15 (DPWR_DAT) several times. When calling up the
SFC15 twice in network 3 (figure below), all 244 bytes of the interface DBs DB22 for
slave 22 – bus 0 are written. In network 4, with two more SFC15 call ups the same data
is put out on slave 22 – bus 1.
Several SFC15 calls are needed as the transferred address range must not overlap the
address range of the single modules of the slave in the hardware configuration. The
maximum length of a module is 128 Bytes.
For more information about to use of SFC15, please see the SIMATIC Step 7 manuals.
