Some device drivers support the configuring of individual device variable security. In order to support this, the device driver will allocate internal memory for the necessary control structures for each variable that the device contains.
On memory resource constrained nodes, this internal memory may take more of the available memory than the application developer wishes to allocate. In this case, the support of individual variable security and the required memory can be disabled. This will result in all variables being treated the same, as far as access control, for all users that have access to the node. This enabling or disabling of individual variable security is done for each device, so the appropriate level of access control and memory usage is flexible.
The default setting for a device's per variable security
parameter, either True (enabled) or False (disabled) will
vary based on the node type.
The following assumes that the device is already created and Stopped.
Follow these steps:
- From the Workbench left pane, expand the node that
contains the device whose per variable security setting
you wish to change.
- Select the Devices icon.
The Devices tab appears on the right pane. - Locate the device, and make sure the device is
stopped.
- Select the device, display its pop-up menu, and
then select Edit.
Or when the device row is selected, select the Edit button at the bottom of the panel.
The Device window appears.
- Under Configuration, make sure
Use Advanced Properties is
selected.
- Select the Per Variable Security
down arrow, and then select
True.
- Select Save.
- Start the device.
- The next step is to go to the Administration window
and use the Security tab to allow read
and write access for each device variable for this
device.
Expand the device name listed under the Devices group for the Read and Write resource. You will see each device variable.
For this example, you would select the symbol next to the device to allow or deny access. For more information, refer to System administration Security.