UDS options on OPC item access rights filtering

[Former Member]

During testing at customer side we discovered heavy problems connecting to third-party OPC servers. Analysing

the OPC reveiled that the OPC server seemed to have a problem with specific access right filters when browsing

the items. This has been verified with the Matricon OPC Explorer as there the access rights filters can be set (row of check boxes). If it doesn't work then no items are shown and can be accessed. That said here are the executed methods:

Does not work:

BrowseOPCItemIDs() - dwBrowseFilterType=2, szFilterCriteria=[], vtDataTypeFilter=0x0000, dwAccessRightsFilter=0x00000003

Works:

BrowseOPCItemIDs() - dwBrowseFilterType=2, szFilterCriteria=[], vtDataTypeFilter=0x0000, dwAccessRightsFilter=0x00000000

Generally there seems to be a problem in interpreting the OPC-Specification. Please also see the following link:

[http://www.opcfoundation.org/forum/viewtopic.php?t=769&sid=09686590183f562cf69816aae9efd42d]

Unfortunately we have no chance to connect to the OPC server via UDS. Neither LUDS nor UDS 4.0 works.

Our guess is that they both work with an accessRightsFilter of 0x3 by default (Read / Write).

Is it possible to somehow configure the access rights filter?

If not it would be very wise to implement such an option to be more interoperable with OPC servers. Would you suggest to open an OSS for this? All the MII introductions with customers are going well apart from massive OPC server connection problems that by far are the most critical parts.

regards

[Former Member]

Definitely should work - open an OSS note. There are some areas of the OPC spec that are open to "interpretation", but security is fairly well defined. There are good reasons to keep the OPC server in "read-only" mode.