Skip to main content
InSource KnowledgeCenter

TN AppSvr235 Modifying the Default Auto I/O Assignments


This article from InSource shows how to modify the default auto I/O assignments in Wonderware Application Server.

  • Author: Rich Brooks
  • Published: 5/17/2017
  • Applies to: Application Server 2014R2 and higher


The auto I/O assignment feature has one default way of formatting the I/O references.  Below is the default I/O assignment format:

<Device Name>.<Scan Group Name>.<Object Name>.<Attribute Name>

Sometimes this does not match the format required by the PLC program.  This may be modified when configuring the I/O mapping from the Integrated Development Environment (IDE).  Start by selecting the device, scan group, or object from the IO Devices view.  

NOTE:  This tech note assumes that the required objects have already been assigned to scan groups for auto I/O assignment.

Changes may be made from the IO Device Mapping dialog as shown below.


The columns labeled Device.ScanGroup Override and Object.Attribute Override are optional.  They are blank by default and ignored if left blank.  The Device.ScanGroup Override column entry replaces the corresponding Device.ScanGroup combination string in the Resulting Reference.  The Object.Attribute Override  column entry replace the corresponding Object.Attribute combination in the Resulting Reference.  These two columns give the developer flexibility in defining the Resulting Reference.  Click on the Apply Pending Overrides button to save override changes.  The Resulting Reference appears in bold to show that it has been overridden.

NOTE:  The IO Device Mapping sheet may be copied and pasted into Excel for editing.  Simply highlight the cells to be copied.  Copy and paste them into Excel.  Modify the Device.ScanGroup Override and/or Object.Attribute Override columns as required.  The columns highlighted in tan above are the only editable columns in the IO Device Mapping dialog.  Copy and paste these two columns only from Excel back into the IO Device Mapping dialog.

Click on the Validate References button to test the overridden reference.  The associated Platform, AppEngine, and DI Object need to be deployed for testing.  Good quality is displayed as green from the Runtime value column.