Point Schemes
A point in CygNet can represent a value from a field device, a scripted point, a point from a third-party system such as an OPC server, can be used to hold a value, etc. A point is required to be defined in your system in order to see the corresponding data on a CygNet Studio screen, in a report, in a trend, or on a web page.
To bring the value of a particular device data group element into the system for viewing, alarm, reporting, and history reporting, you must create a point in the system that represents the UDC mapping of the element.
The Current Value Service (CVS) caches the point configuration information of all of its points. When it obtains a value for a point, it checks the configuration and processes the data accordingly. If necessary, it passes the information to other services such as the Common Alarm Service (CAS), the Value History Service (VHS), and the General Notification Service (GNS).
In general, the method used to resolve data for a point is based on the point’s Current Value Service (CVS) type. CygNet supports four CVS types, that each resolve point data based upon specific attributes as listed in the following table.
| Current Value Service (CVS) Type | Basis of Point Resolution |
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Facility and UDC Non-facility points can also be created. Use setpoint tasks to perform updates for these points. See PNT Editor - General Properties for more information. |
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External ID See PNT Editor - Point Reference Properties for more information. |
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Script See PNT Editor - HyperPoint Properties for more information. |
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Facility and UDC See PNT Editor - General Properties for more information. |
CygNet supports four data types, for input or output.
The Point Service (PNT) is the CygNet point database service used to set operational parameters for real-time points in the CygNet system. A point record contains all configuration information about a point, including the name of its current value service (CVS), its Facility, Uniform Data Code (UDC), the Short ID and Long ID, description, engineering units, history retention period, alarm setpoints, scaling factors, notification options, enumeration conversions, etc.
The PNT manages alarm limits, conversion coefficients, description information, and other parameters necessary for real-time monitoring and control. One PNT can store point records for any number and any type of current value service (CVS). A point is required to see the data on a CygNet Studio screen, in a report, in a trend, or on a web page.
More:
Point State and Alarm Condition
Scaling Analog Input Point Values
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