Troubleshooting AVEVA / OSIsoft PI Asset Framework (AF) export channels (such as XML exports, AFExport.exe utility, or PI Builder transfers) requires isolating configuration, dependency, and security faults. When an export channel stalls or throws an exception, the data pipeline halts.
Here is a comprehensive breakdown of common AF export channel errors, their underlying causes, and direct fixes.
1. “Object Reference Not Set to an Instance of an Object” (NullReferenceException)
The Cause: This occurs when you try to export an asset hierarchy containing broken references or orphaned dependencies. For example, an AF Attribute points to a PI Point or an AFTemplate that was deleted. The Fix:
Open PI System Explorer (PSE) and locate the source element hierarchy.
Right-click the top-level element and select Check In to ensure no pending uncommitted deletions exist.
When using the AFExport.exe command line or AF SDK scripts, always include the /AllReferences parameter (or PIExportMode.AllReferences). This forces the exporter to recursively gather and bundle all linked templates, categories, and reference types rather than choking on an unlinked element. 2. “Server Does Not Support Features” / “Version Mismatch”
The Cause: Exporting an XML configuration from a newer PI AF Server version and importing it into an older target server often fails. You will see errors like “The version X of PI AF Server does not support [Feature Y]” (e.g., Externally Linked Tables with Non-Impersonated Users). The Fix:
Verify the source and target server versions by checking the Help > About menu in PSE.
If a version mismatch exists, avoid the standard bulk XML channel. Instead, use PI Builder in Microsoft Excel to select only the standard attribute rows, or downgrade the target server feature requirements by unchecking complex options (like external table impersonation) before exporting. 3. “Cannot Connect to PI AF Server” or Timeout Errors
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