OPC UA server historical data access

Hello,

When I use other software, such as Labview, to build an OPC UA client to access the dewesoft OPC UA server, can I fetch the data from a past time to the current time? Because when the channel data changes very frequently, I am worried that I will not be able to read all the data through subscription or timed reading method.

Dear Haoyan Gu,

In theory, it is possible to read the data back for one acqLoop (values node inside the ChBuffer).

In practice, however, the CurrentScaledValue node is usually sampled. And yes, your worries are justified. It can happen that you miss a sample. But OPC UA was never meant for fast sample rates.

Best Regards.