Siemens S7 Series - Mode of Operation; Data Points and Signal Chart

3 Mode of Operation
Communication with S7 CPU via KNX Gateway
Entry ID: 109739689, V1.0, 06/2017
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 Siemens AG 2017 All rights reserved
3 Mode of Operation
The data between the two bus systems, PROFINET and KNX, is exchanged
between the drivers (PROFINET, KNX) in the gateway via data point mapping.
The data points are described in the pnetd1.txt and eib1.txt configuration files and
mapped to each other in the dispatch.txt dispatch file.
For each data point, the format specifies how the driver should interpret the data at
the data point address.
3.1 Data points and signal chart
Each interface of a device (CPU, KNX) that is used to transfer data represents a
data point. As the gateway connects two different bus systems, it has two data
points – the source data point and the target data point.
The example in the following figure shows a signal that is generated in the S7-1200
CPU and transmitted to the gateway via PROFINET. The gateway converts the
PROFINET signal to a KNX telegram and sends it to the appropriate group address
of the KNX device. In the same way, a signal can also be transmitted from a KNX
device to the S7-1200 CPU.
Figure 3-1: S7-1200 CPU  KNX device – signal chart
E
PROFINET KNX
Gateway
Q
outbit
outbyte
GA
S7-1200 CPU
KNX device
Signal chart
Q
Signal
Data point
E
GA
E
PROFINET KNX
Q Output
GA Group address
For the KNX driver and all other gateway drivers, the following types apply to the
definition of the data types:
Table 3-1: Definition of the data point types
Type
Meaning
M
Integer value (binary data points, counts) that can only be read by the gateway.
S
Integer value that can be read and written by the gateway.
X
Analog value (with decimal places) that can only be read by the gateway.
Y
Analog value (with decimal places) that can be read and written by the gateway.
For a definition of “data points”, please refer to the gateway manual (\3\), section 6
“Protocol properties and data points”.