Points not updating. What are the most common causes?

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The example below is intended to demonstrate one or more features or methods and is presented as a configuration example only. Schneider Electric assumes no liability for the use or application of this example or any portion thereof.

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Sometimes the communications look good, but the points are not updating as expected, either current values, historic values or both.
Below the most common causes for it:

Significant Change Property

Significant change configuration ("Analog Point" tab) in Advanced Drivers (DNP3, AdvancedModbus) is the most common source of confusion for customers. Most people would believe that the "None" option means that the point will be updated for any variation read from the field, but, for Advanced Drivers, "None" means that the server only updates the point value in the ClearSCADA database when one or more of the following occurs:

• The point changes state
• The point’s Scan Group interval expires (this applies to points on outstations that are using direct, rather than PSTN, communications to talk to the server)
• On start-up of a call to an outstation (this only applies to points on PSTN outstations)
• The Refresh action is triggered for the outstation on which the point resides
• On system or driver start-up.

In other words, in normal operation, the point will be updated in ClearSCADA only at start-up. So it is important to choose another option for "Significant Change", either "Absolute" or "Percentage of Span".
Even the option "Percentage of Span" may not result as the customer expected . Sometimes the customer has a point that goes, for instance, from 0 to 10 and a range set from 0 to  32000 in the configuration. In this case he needs to adjust the "Zero Scale" and "Full Scale" to match the real range of the point.

DNP3 point configured as "Local" in the E-Series controller

DNP3 points must be assigned to a class (0, 1, 2 or 3). If it is left as "Local" (default setting when creating a new point), CS will not read the points, unless a "Level 3 scan" is triggered.

DNP3 point "Logged Data > Historic Data Filter" not set properly
You can choose from:

• None—ClearSCADA does not log any data that the outstation reports for this point, into the ClearSCADA historic database.

ATTENTION: This setting overrides any settings configured on the Historic tab.

• Static Data Only—ClearSCADA logs only the point data that is returned in a DNP3 Class 0 Poll or Level 3 Scan. This data includes the present state or value of the point.
• Event Data Only—ClearSCADA logs only time stamped DNP3 Event data into the ClearSCADA historic database. Such data might include a change of state, or a value that has exceeded a limit.

ATTENTION: ClearSCADA will not log any point data historically if the Event Data only option is specified for a point that is configured in the outstation to report only Class 0 Static data, or if the point’s value is read using a DNP3 Level 3 Scan.

• Static and Event Data—ClearSCADA logs all data that the outstation reports for the point, provided that the settings on the Historic tab are appropriately configured.

Udgivet til:Schneider Electric Danmark