Receiving error: The server denies access (read and/or write) to the specified item. ViewXScript

[dtappen]

I have a script that is attempting to write to the ".LowLimitStd" property of an analog point.  The error "The server denies access (read and/or write) to the specified item. ViewXScript" is thrown when the method "server.setopcvalue(fullname.lowlimitstd, value)" is called.

What is unusual, is that this same script works for other analog points.  Is this a security properties issue or some other setting or "checkbox" that needs to be set?  If security, what permissions are missing?  This script is being called from a popup form, which I assume means that it is running in the security context of the ViewX logged in user.

[geoffpatton]

My guess is the point is in a instance of the template and that the low limit has not had its override enabled.

You certainly could have security permissions applied. To check just right click on it in the database tree and select Edit Security.

You can also try using the super user from the ViewX on the server and see what happens.

[tfranklin]

Geoff is on the right path.  My guess is overrides.  Second guess would be permissions (Maybe it's a new tag that isn't inheriting permissions or something). 

[dtappen]

Thanks for the replies.

We did some experimentation and determined the issue.  As it turns out, the object was missing the "configure" permission for the operator.  We turned this on and it's working now.  This does however bring up a different question.  Is it possible to define a script or method to run under a different security context?  The script in question is used to perform some automation over alarm limits.  While the script is triggered by the operator, we do not necessarily want the operator to have direct ability to change alarm limits.  Execution is as follows:

Operator clicks button on screen to popup data entry form.

Operator clicks button on form to accept values and execute "limit update" script.

Limit update script writes limits via "server.setopcvalue" method (which needs to run under different security context).

[geoffpatton · Accepted solution]

thw only workaround I have found is to use a ST program. The program logic can do configuration changes, but has a setable execution permission in its configuration. I did that for a refresh button set to read permission so any logged in user could force a outstation refresh.

[sbeadle]

I recommend Geoff's solution. You should limit access to the Logic program execution though.

Note that alarm limit tuning is a feature created for this purpose though - allows operators to make temporary limit changes. Some users create a table of tuned limits for a person with higher privileges to 'approve' and write to the permanent limits using script.