Resolution is the process of determining additional properties about each OPC items that is being trended. For SapphireTrend, the item properties used for resolution are the item Description and Engineering Units. Once 'resolved', these properties are used throughout the product to provide additional context about the items being trended.
Sapphire Trend provides two resolution 'modes', namely Automatic and Manual. The resolution mode can be set for each individual item that is to be trended.
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Control: |
Description: |
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Description |
A textual description of the currently selected OPC item. |
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Units |
The Engineering units for the currently selected OPC item. |
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Type |
The mode of resolution required. Options are Manual or Automatic (see below). |
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Resolved |
Checked if the Item has been resolved (Read Only) |
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Resolve |
Click this to request that the item is re-resolved. |
Automatic Resolution
When an item is set to Automatic resolution mode, the collector will query the underlying OPCServer for the Engineering Units and the Description of the item being trended. OPCServers which do not support these item properties will return an error code meaning that the item will be marked as having failed resolution.
Notes: Automatic resolution is only performed once. Once an item is resolved it's additional details will not be re-read. To refresh the information the user should manually request that the item is re-resolved (via the Resolve button).
When in Automatic mode the Sapphire Collector resolves items at the resolution frequency defined when the SDR was created.
Tip: Where items fail automatic resolution (most likely due to the OPCServer used not being able to return the attributes) then the item should be put into Manual resolution mode.
Manual resolution
Where the underlying OPCServer does not provide the Engineering Units and Description attributes for items, the user has the option of selecting Manual Mode and entering the information by hand.
Note: Items that are in Manual mode are never automatically resolved.
If new items are added then it is possible to manually demand an immediate resolution of all items with the SDR that are currently unresolved. To do this use the Resolve button.