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Retrieving data from the OPC UA server for a time interval in which the connection to the server was lost

Posted: Mon Mar 04, 2019 3:04 pm
by vadim
Hello,
I have problem with automatic retrieving data from the OPC UA server via WinCC OA OPC UA client for a time interval in which the connection to the server was lost.

WinCC OA help:
"Writing the data to data point element with appropriate peripheral address: This allows to automatically insert the received data into the _archive config of all data point elements with the appropriate peripheral address. Therefore, it is possible to retrieve data from the server e.g. for a time interval in which the connection to the server was lost."

I configured WinCC OA OPC UA client for writing the data to data point element with appropriate peripheral address and it works fine for manual requests. But it doesn't request data automaticaly for a time interval in which the connection to the server was lost.

WinCC OA version 3.15 P015. I tried to use different opc ua servers: UaAnsiCServer, WinCC OA OPC UA Server

What is mean phrase from help "e.g. for a time interval in which the connection to the server was lost."? Is it sould work automaticaly, or I need to implement this functionality?

Re: Retrieving data from the OPC UA server for a time interval in which the connection to the server was lost

Posted: Tue Mar 05, 2019 8:56 am
by leoknipp
The part of the documentation you have copied into your posting is part of the OPC UA HA (Historical Access) documentation.
If you want to use this functionality you have to use an OPC UA server which support historical access.

Best Regards
Leopold Knipp
Senior Support Specialist

Re: Retrieving data from the OPC UA server for a time interval in which the connection to the server was lost

Posted: Tue Mar 05, 2019 10:34 am
by vadim
Historical access is supported by server and I can retrieve data by sending command thru internal datapoint (DPT is _OPCUAServer)

For example,
Connection to the server was lost between 2019.03.04 19:51:09.000 and 2019.03.04 19:52:10.000.
I write command into _OPCUAServerDPname.Command.HistoryRead and retrieve data directly to _archive config of all data point elements with the appropriate peripheral address .
The question is, can I configure WinCC OA to do it (or something similar) automaticaly?

Example of command:
RequestId8779
ReadRaw
3
*
2019.03.04 19:51:09.000
2019.03.04 19:52:10.000
1000
1
_testResponce

Re: Retrieving data from the OPC UA server for a time interval in which the connection to the server was lost

Posted: Wed Mar 06, 2019 1:22 pm
by leoknipp
There is no automatism available which sets the dp element to retrieve historical data.
You can implement your own script which performs the following steps
-- detect when the connection is lost
-- detect when the connection is reestablished
-- encode the information and write it to the dp element

Best Regards
Leopold Knipp
Senior Support Specialist

Re: Retrieving data from the OPC UA server for a time interval in which the connection to the server was lost

Posted: Wed Mar 06, 2019 3:00 pm
by vadim
leoknipp wrote: Wed Mar 06, 2019 1:22 pm There is no automatism available which sets the dp element to retrieve historical data.
You can implement your own script which performs the following steps
-- detect when the connection is lost
-- detect when the connection is reestablished
-- encode the information and write it to the dp element

Best Regards
Leopold Knipp
Senior Support Specialist
Thanks a lot!