Siemens S7 Plugin

1 Installation

1.1 Download

DEWESoft homepage ( you can download DEWESoft plugins when you go to: Support → Downloads → Plugins

1.2 Compatibility

The plugin is compatible with DEWESoft 7.1 and DEWESoft X. It has been tested on Windows 7, Windows 8 and Windows 10 (32-bit and 64-bit).

1.3 Licensing

In DEWESoft an additional license for the plugin is needed, it can also be written into the Dewesoft device. The plugin requires a valid DEWESoft license. To test the plugin you can use a 30-days-Evaluation license.

1.4 Plug-in Installation

The file contains the file SiemensS7.dll. Please copy the file into the Addons folder of your DEWESoft installation. (e.g. D:\DEWESoftX3\Bin\X3\Addons), then start DEWESoft. In Options → Settings → Extensions, click the “+” button and to add the plugin, click the checkbox. The plugin will show up in the list.

2 Configuration

The Siemens S7 Plugin enables the communication with Siemens PLC devices via S7 protocol over Ethernet. As this is a direct communication between the plugin and PLC devices, no Siemens licenses are required.

The current version of the plugin supports reading of S7 data. All S7 data types are supported (Bool, Byte, Char, Word, Int, DWord, DInt, Real, Date, Time Of Day, Date_Time, String).

Furthermore, the plugin supports simultaneous communication with multiple PLC devices.

2.1 Setup screen

Request period (1) corresponds to the PLC request interval, i.e. at what interval PLC requests will be sent. For instance, 1000 ms request period will result in 1 Hz request rate, whereas 100 ms request period will result in 10 Hz request rate.

PLC location settings (2) contain general PLC settings such as PLC IP address, rack and slot number etc. Whenever the user clicks the Add new channel (3) button, a new channel with the current PLC location settings will be added to the channel grid (5).

If a particular channel is selected, it can be deleted by clicking the Delete selected channel (4) button.

Besides the typical columns, common to the other Dewesoft plugins (such as Used, Channel name etc.), the Channel grid (5) also contains the following columns:

  • Data type: data type to retrieve from PLC device:


  • Display: controls how the variable will be displayed (decimal, hex, binary)

  • Offset (bytes) and Offset (bits): define the variable offset which is calculated as Offset (total) = Offset (bytes) + Offset(bits)

  • Data area: data area of the variable (currently only DB is supported)

  • IP address (read only): IP address of the PLC device

  • Rack (read only): Rack number

  • Slot (read only): Slot number

  • DB Id (read only)

3. Measurement

Go to Measure mode. The channel list on the right will show the decoded output channels of the plugin. The plugin generates PLC requests (at the rate defined by Request period) and stores the values retrieved to the corresponding channels.