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CNCnetPDM OPC DA for Siemens Sinumerik 840D controllers enables you to acquire and monitor machine-, process- and quality-data from your machines from a remote PC. It also allows to write and change parameter values on these devices.


This document describes setup and test of data acquisition and writing of parameter values from/to Sinumerik controllers that use OPC Classic which is most likely the case if your controller has a Microsoft Windows OS and does NOT run Sinumerik Operate >= Version 4.5.

Sinumerik 840D CNC

FIG 1: Sinumerik 840D CNC


Start up the controller in service mode without HMI.

It is recommended that you turn off simple sharing: Click Start->Run type in eplorer.exe click on Tools->Folder Options. In tab View uncheck ‘Use simple file sharing (Recommended)’. Click OK.

Firewall settings (Controller)

If you have the firewall enabled at the controller proceed as follows: The most simple way to avoid communication problems is to turn off the firewall. Click on Start->Settings->Control Panel->Windows Firewall. Click on Off (not recommended) followed by OK. You’re done.

If you want to keep the firewall switched on you have to adjust some settings.

  1. Add Port 135 to exceptions
  2. Check ‘File and Printer Sharing’
  3. Add program ‘Simatic OPC Server’ (..\mmc2\opc\dataaccess\SOPC_MachineSwitch.exe)*
  4. Click OK

* Depending on the setup of your controller these files may be stored at a different location.

Sinumerik firewall settings

FIG 2:    Firewall settings on Sinumerik 840D

Restart the controller in normal mode to enable HMI again. TOP 



  1. Either click on Start->Programs->Administrative Tools->Component Services or
    Start->Run and type in dcomcnfg and click OK
  2. Expand Component Services->Computers->My Computer
  3. Right click My Computer select Properties
  4. Open tab Default Properties
  5. Make sure that Enable Distributed COM on this computer is checked
  • Important: In case your PC runs an Operating System > XP, e.g. Windows 7 AND the controller PC runs Operating System Windows NT 4.0 you mandatorily have to set 'Default Authentication Level' in tab 'Default Properties' to 'None' otherwise you just get an 'Access denied' output from the test programs and the device driver! You also have to reboot your PC for these changes to take effect.


For successful communication between PC and controller it is necessary that the querying computer is able to access the controller and its Operating System via the network with proper credentials!

Typically the account you’re using on your PC does NOT have the rights to access the controller. To resolve this you need to setup an additional account:

  1. Right click ‘This PC’ on your desktop and select Manage
  2. Expand Local Users and Groups
  3. Right click on ‘Users’ and select ‘New User’
  4. In ‘User name’ enter ‘auduser’ (without quotes)
  5. In ‘Password’ enter the password for user ‘auduser’ used at the controller, (typically ‘SUNRISE’)
  6. Confirm the password, uncheck ‘User must change password at next logon’, click button Create followed by Close
  7. Right click on username ‘auduser’, select Properties
  8. In tab ‘Member Of’ click button Add and type in Administrators, click button Check Names followed by OK
  9. Close the Properties dialog by clicking on OK

Test access to your controller:

  1. Create a shortcut to explorer.exe (%SYSTEMROOT%\explorer.exe) on your desktop
  2. Next, right click the shortcut with the shift key pressed and select ‘Run as different user’
  3. Type in the name of your PC followed by a backslash and auduser (e.g. MYPC\auduser) followed by its password
  4. In the address field input two backslash characters followed by the IP Address or DNS Hostname of your controller e.g. \\ and press enter. You should get access to your controller TOP 




If you have installed CNCnetPDM on your PC with a license other than a ‘free license’ and run this program from the folder where CNCnetPDM is installed you can modify all OPC Items. Otherwise you can monitor, read and write all predefined OPC items. Please see licensing for details or contact us if you have any questions.

  • Note: If you like to run this program from a different location on your PC you can simply copy your CNCnetPDM.ini file to this directory.


Extract all files from to a folder on your PC.

In case you use a firewall at your PC or your company network please make sure that there is an exception for TCP Port 135. As the ports for OPC communication are dynamically assigned you also have to add an exception for program CNCnetPDM.OpcDA.SimpleClient.exe. You can use our tool Device Port Scanner to check if your controller is reachable via port 135.

  • Note: The program requires .NET Framework 2 components to be installed on your PC.
  • Note: If your PC does NOT have any OPC programs installed you need to install the x86 version of the OPC core components:



The program enables you to connect to your controller via OPC DA (Classic), monitor, read and write items.

Right click CNCnetPDM.OpcDA.SimpleClient.exe with the shift key pressed and select ‘Run as different user’. Enter user name ‘auduser’ and its password.

In CNCnetPDM.OpcDA.SimpleClient.exe enter the DNS Hostname or IP Address of your controller into the textbox right to [Connect] (1).


Connect Sinumerik 840D DA Client

FIG 3:    Connect CNCnetPDM.OpcDA.SimpleClient

Click [Connect] you now should be connected to the OPC DA server on your controller.

Sinumerik 840D OPC DA Client

FIG 4:    CNCnetPDM.OpcDA.SimpleClient

Initially one item is queried, by changing ‘Active Items’ (1) to a different value you can activate up to 15 items.

The 15 predefined values under ‘ItemID’ are known to work well on most controllers. With a licensed version you can change them according to your requirements. The last two items are 2 writable R Parameters (user variables) that are visible at the controller: [MENU SELECT] -> [Tools Zerooffs] -> [R Variable].

If you click on button Read (3) the values of all active items are queried from the controller and shown in the dialog.

For the last two variables R1 and R2 you see their current values as set at the controller.

By entering different values for these two writable items and clicking on [Write] (4) you can change their values at the controller.

Clicking on [Monitor] (2) adds all active variables to a subscription and shows their current value.

Note:   In the zip archive you can also find file ‘Querieable_Values.txt’ that contains a list with 1630 variables that can be queried from Sinumerik 840D controllers.

If you’re done, click on [Disconnect]. TOP


In case of errors the program outputs an error log file that can be found in the directory where the program is located. This file contains detailed information about any errors.

If you see a popup window with CoCreateInstanceEx: Access is denied make sure that you run the program as user ‘auduser’.

If you see a popup window with CoCreateInstanceEx: The RPC server is unavailable check that the controller is running, you typed in the correct IP Address and you configured your firewall correctly.

If you see values like Exception from HRESULT: 0x… in one of the output fields when reading or monitoring check that you typed in the item id correctly. In case of writing check that the item is writable e.g. a r-parameter and you didn’t type in an improper format e.g. alphanumeric instead of numeric. TOP


Steps for booting the PCU in service mode:

  1. Switch on the PCU.
  2. When the prompt 'Please select the operating system to start:' is displayed, press the KEY until the line below SINUMERIK is highlighted in white.
  3. Confirm the selection by pressing the INPUT KEY.
  4. The service menu opens:

Service Menu

FIG 5:    Service menu
  1. Select the menu option: 4 Start Windows (Service Mode).
  2. Then select the menu option:
  3. Standard Windows (without starting SINUMERIK HMI)
  4. The PCU restarts.
  5. When prompted to enter "Password:" Enter your service password (default: SUNRISE)
  6. This password authorizes you to make extensive changes to the control. The password must be entered in upper case letters.
  7. After the PCU has booted in service mode you can configure MS Windows components.TOP

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