System Digital States Written to Tags

System Digital States Written to Tags

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  All tags are set to Intf Shut at interface shutdown, or the state specified in the /stopstat=state parameter.
  
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  When the interface fails to establish a point in the ICI module, the related PI tags are set to the digital state Configure.
  
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  When a tag is removed from the interface, the tag status is set to No Data.
  
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  If there are 10 sequential failures in obtaining exception data from Bailey semAPI, the interface will set all tags to No Data.
  
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  An input tag is set to Bad Input if Bailey’s BAD QUALITY flag is set or if a digital value is out of range for that tag.
  
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  An output tag is set to Bad Output if the PI value is a digital state code such as Shutdown or OverRange.
  

PointSource

The PointSource is a unique, single or multi-character string that is used to identify the PI point as a point that belongs to a particular interface. For example, the string Bailey may be used to identify points that belong to the Bailey semAPI Interface. To implement this, the PointSource attribute would be set to Bailey for every PI Point that is configured for the Bailey semAPI Interface. Then, if /ps=Bailey is used on the startup command-line of the Bailey semAPI Interface, the Interface will search the PI Point Database upon startup for every PI point that is configured with a PointSource of Bailey. Before an interface loads a point, the interface usually performs further checks by examining additional PI point attributes to determine whether a particular point is valid for the interface. For additional information, see the /ps parameter.

Case-sensitivity for PointSource Attributes

In all cases, the point source character that is supplied with the /ps command-line parameter is not case sensitive. That is, /ps=B and /ps=B are equivalent. One only needs to be careful with the case of the PointSource during point definition, and only if the interface will be running on a PINet node communicating to a PI 3 Server.

Reserved Point Sources

Several subsystems and applications that ship with PI are associated with default PointSource characters. The Totalizer Subsystem uses the PointSource character T, the Alarm Subsystem uses G and @, Random uses R, RampSoak uses 9, and the Performance Equations Subsystem uses C. Do not use these PointSource characters or change the default point source characters for these applications. Also, if a PointSource character is not explicitly defined when creating a PI point; the point is assigned a default PointSource character of Lab (PI 3). Therefore, it would be confusing to use Lab as the PointSource character for an interface.

Note: Do not use a point source character that is already associated with another interface program. However it is acceptable to use the same point source for multiple instances of an interface.

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