OPC Server not polling the field values

[aqeel_haider]

Dears

I am using Clear SCADA and Sofrel Data loggers. For this i used Simple OPC Server to collect the information from Data loggers. I am facing this issue that if i configure Read Mode as Asynchronized then i found the difference between Current Value and Histories' Value.  And Current Value updating on time. 

I cross check through OFS Client and found both Value and HValue have same values on their register.

Then i configured Read mode as Synchronize then i found that HValue and Values are the same but not updating once value will change. And there is a Lag of 2 days in updating.

Is there any way to refresh the server on specific time to collect the information ? Or how can be solve this issue.

[AndrewScott]

Can you explain what you mean by "Histories' Values"?

The OPC DA standard only deals with current data, not historical data.

Is this some special feature of the Sofrel data logger?

In asynchronous mode the OPC DA client (Geo SCADA) subscribes to updates from the OPC DA server (Sofrel). It's up to the server (Sofrel) to then push changes to the client (Geo SCADA) as they occur. This is the most efficient mode.

In synchronous mode the OPC DA client (Geo SCADA) periodically polls the OPC DA server (Sofrel) to get data. The "Scan Rate" and "Scan Offset" settings on the scanner define when the polls occur. See Configure the Scanner Properties 

NB. The Geo SCADA simple OPC driver is a legacy driver for backwards compatibility. The advanced OPC driver should be preferred for all new systems.