Baumer GK473 - Manual (Page 22)

Manual_GK473_S7_Profibus_EN.doc 22/32 Baumer IVO GmbH & Co. KG
04.05.11 Villingen-Schwenningen, Germany
By double click to the new AWL (STL) source file a window showing the function’s source code will
open. Afterwards the source file is stored and the program returns to the SIMATIC manager.
Now the project source file must be compiled. Use right mouse key and click to ÆCompile to AWL
(STL)-source file ( in the following FC2) of the SIMATIC-Manager.
3.13 Transferring PLC commands to SPA by gateway
As described in the GK473 manual, possible commands of gateway to SPA have basically the same
structure. For example, a count byte marking the beginning of a new RS485 telegram is followed by
the SPA identifier and then by the true command. Other data may also be attached, for example a
target and/or profile number to write. This Profibus data block has a permanent length of 16 bytes and
must always be transferred in a consistent way.
For consistent transfer Siemens provides the system functions SFC14 (read) and SFC15 (write), that
in our example transfer (SFC15) respectively store (SFC14) 16 bytes each of a data block.