Communication with S7 CPU via KNX Gateway 
Entry ID: 109739689,    V1.0,    06/2017 
 
 Siemens AG 2017 All rights reserved 
2.2  Description of the core functionality 
Configuration 
The connection between the S7-1200 CPU and the gateway is configured via 
  the configuration of the gateway as distributed I/O in STEP 7 (TIA Portal). 
  configuration files of the gateway (cfg and txt files) (see Figure 3-3) that 
reference each other. 
The configuration files are downloaded to the gateway using the integrated web 
server or directly edited. 
Configuring and programming the gateway requires no ETS software. The gateway 
can access existing data points (group addresses) in the KNX network and provide 
its own data points locally on the gateway.  
The assignment of the devices’ group addresses and physical addresses is not 
part of this description. For more information, please refer to the supplied ETS5 
sample project. The gateway’s physical address (KNX) is set using the “eib1.cfg” 
configuration file (see 4.4.3). 
Function and data types 
This application example contains a STEP 7 project and a data record for the 
gateway, where data of different data types is exchanged between an S7-1200 
CPU and KNX devices in both directions via the gateway. A decimal value is 
transferred from the S7-1200 CPU to the KNX control room unit’s display and a 
status LED of the KNX wall switch is controlled via a binary signal. Conversely, the 
value of the integrated temperature sensor and a configurable decimal value are 
transferred from the KNX room control unit. Using the KNX wall switch, a boolean 
variable is set/reset in the S7-1200 CPU. 
 
The following data types are used and parameterized: 
Table 2-2: SIMATIC / gateway data types