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Ascherer17
Ascherer1716-Pearl
16-Pearl
March 22, 2018
Question

Remote Binding Cache for # Seconds Issue

  • March 22, 2018
  • 1 reply
  • 3491 views

I'm using Thingworx 7.1 with the KEPServerEX extension and KEPServerEX 6.2.

I'm testing some of the settings to figure out how we may be able to log values periodically rather than based on a value change.  I ran the AddItems service to add one of KEPServer's simulation sine wave function tags multiple times to the RemoteKEPServerEXThing so I can compare some property settings. 

I've been playing with the Cache Options under the Remote Binding Info of the Sine properties.  The default is usually "Read from Server Cache" with Push Type set to "Always".  I'm finding that if I switch Cache Options to "Cached for # seconds" (interval of 2-5 seconds) and Push type to "Never", the value never updates.  Also I set Data Change Type to "Always" so the value will log to a Value Stream every time it gets an update.

The ? button on Cache Options gives this:

  • Cached for # Seconds allows you to control the frequency by which requests to the Edge Property are made. Upon the first request the server will access the Edge Property for it's value, then not make another request to the Edge Property per the defined number of seconds, though the Edge Property may update the server value (via push) in that time frame.

 

If I query the property history, there's no values coming in although if I click refresh in the Properties screen of my KEPServer thing, the sine property DOES change every # seconds and a value is logged but only if I click refresh.  We can't have somebody manually clicking refresh to update values though. 

Anybody else observe this before?  Any ideas what's keeping the values from being updated every # seconds?

Thanks

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1 reply

Ascherer17
Ascherer1716-PearlAuthor
16-Pearl
March 22, 2018

To update my findings:

AddItems allows you to give a specific scan rate for each tag item added.  This seems to be an alternative as my KEPServer Thing only receives a value at the rate I give.  

I'm not sure yet if you can readjust that scan rate for an item without removing and readding the item.  Seems inconvenient to have to delete property and run AddItems again just to change the scan rate.  

 

S
stmarchessault5-Regular Member
5-Regular Member
April 12, 2018

Greetings @Ascherer17,

 

There have been many releases of ThingWorx since the version you are working with. Improvements have been made to the layout and design of Remotely-bound Properties, especially those bound to KEPServerEX tags. In the newest version of Composer (NextGen Composer), you can now set the Scan Rate on the fly within the Remote Property attributes. I think you would generally find the interface much easier to use, especially after using the AddItems method in 7.1.

 

For more information on the steps followed to connect KEPServerEX with ThingWorx via the IndustrialGateway in the current releases of both applications, see this document:

 

Industrial Connections Example

 

Going back to your original question, a Push Type of "Never" will prevent the Edge (KEPServerEX) from Pushing its Values into the server cache. It makes sense that you are seeing no Value updates with this configuration.

 

Do you find the updates resume when you set the Push Type to "Always"?

 

 

Best regards,

Steven M

    Ascherer17
    Ascherer1716-PearlAuthor
    16-Pearl
    April 12, 2018

    If I set the push type to "Always", the updates come through to Thingworx.  It seems that the Thing's properties change on every update though, rather than on the period I tried to set with "Cache for # seconds."

    I know there have been a lot of improvements in newer releases.  Plans are in the works for updating; we just have some issues to address first.  

    It's good to know that you can change the scan rate easily!

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