Registry Filter

Through the Registry filter it is possible, using a write filter (EWF or FBWF), to write individual registry keys permanently, without having to "commit" the entire registry files after each change.

The registry key [HKLM\SOFTWARE\Beckhoff] is released by default so that TwinCAT can save settings in the registry. Custom "write releases" can be created under the key. A subkey with a sequential number must be created for this.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Regfilter\Parameters\MonitoredKeys\2]
"ClassKey"="HKLM"
"RelativeKeyName"="SOFTWARE\\Beckhoff"
"FileNameForSaving"="Beckhoff.rgf"

ClassKey = higher-level regkey

RelativeKeyName= relative key that is to be released for write accesses.

FileNameForSaving= file in which the key is saved.

Deactivating the Registry filter:

At the moment it is only possible to deactivate the Registry filter via the registry.

  1. Open the Registry Editor (Start-> Run...-> enter "regedit").
  2. Now navigate in the tree on the left-hand side to the registry key: "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Regfilter".
  3. Now change the value of the Start parameter from "1" to "4".

Activating the Registry filter:

To activate, perform steps 1 & 2 again.

Then change the value of the "Start" parameter back to 1.