SINUMERIK S7 TCP OPC UA server enables the connection of Siemens SINUMERIK CNCs, including the 840 Dsl and 828 Dsl models, and other models through Ethernet, utilizing the S7 TCP protocol. This allows for remote communication with the CNCs.

However, in situations where external communication via S7 TCP is not possible, the OPC UA server can be installed directly on the operator HMI. This allows the server to communicate with the CNC and PLC via S7 TCP protocol through internal Ethernet network instead of relying on external communication protocols.


version: v2.7.0

published: Jun 03, 2024

Download 64-bit installer for Windows - 1.6 MB

Download 32-bit installer for Windows - 1.28 MB

Download 32-bit installer for Windows XP Service Pack 3 - 1.2 MB


Installation process is very simple and straight forward. Installer copies the following files to “%PROGRAMFILES%\X-tensive\DPA.UA\s7nck\“ directory:

Firewall exception is added for executable.

If there is no certificate or private key for OPC UA server default instance, a self-signed certificate as well as private key are generated and placed to “instances\default\“ subfolder.

Installer is a simple console application that requires no user interaction or parameters. All output is sent to stdout and stderr. It is fine to run installer under SSH session. Here is a typical output:

dpa installer, 64-bit
Destination: C:\Program Files\X-tensive\DPA.UA\s7nck\
Copying ""... ok
Copying ""... ok
Generating default certificate... ok
Will configure firewall...
  exception for ""... ok
installation SUCCEEDED!

Update of running services

In case when a previous version was already installed and OPC UA server instances are up and running as Windows services, the installer will do update correctly. First, all running services of OPC UA server are shutdown gracefully. Old binaries are replaced with a new version. Finally, all previously running instances are started again.

Update of interactivelly running processes

In case when OPC UA server runs as interactive console process, installer kills this process before installation to release any locks of old binaries, otherwise installation and update of the binaries would fail. The installer does not attempt to restart interactive processes after binaries update.

Command line arguments


Optional. Specifies instance name for non-default instance. Instances are explained here.


Optional. Specifies TCP port for OPC UA server. Default is 4840.


Optional. Indicates that OPC UA server should not use x509 certificate and private key. Only unsecured OPC UA server endpoint is hosted. Avoid to use it in production environments.


Specifies SINUMERIK device host and port. Host can be a network name or IP address. Port is optional, default is 102.


Optional. Indicates that NCK address space should be initialized. TSAP number is optional, define it only for non-standard NCK device TSAP number.


Optional. Indicates that PLC address space should be initialized. TSAP number is optional, define it only for non-standard PLC device TSAP number.

Both NCK and PLC TSAP numbers can be defined as decimal or hexadecimal numbers. Use “0x” prefix for hexadecimal, for instance, “/nck:0x307”

Here is an example of connecting SINUMERIK device with IP address and default TCP port 102, both NCK and PLC adress spaces are initialized:

dpa.opcua.s7nck.exe /dev: /nck /plc

Basic configuration

The installer does not register any windows services automatically. To register a new windows service instance do the following: /install /dev: /nck /plc

To list all installed instances: /list

Typical output:

  instance: (default)
  port: (default)
  nck: (default)
  plc: (default)
  start type: auto
  status: running
  instance: M027
  port: 4841
  nck: (default)
  plc: (default)
  start type: auto
  status: stopped

To start default instance:

net start DPAOPCUA.S7TCP