Thanks for the fast reply.


regarding point 4: Here i should have be more precise. Let's pretend a try to write a single item in a very short period e.g. 10 times with 50 ms. Do i have to expect that each change will be written to the server or will it be written into something like a cache and only cause one (or depending on timing) write operation?

Nevertheless my Application must take more responsibility. So basically, i will create a Queue in my Application. The Businesslogic itself will only write into our internal Queue and a seperate Task/Thread will take all the items from the queue and trying to write it to the OpcServer.

hi,

i'm currentliy working on a tool that is writing some values via opc. Unfortunatetly i don't get how WriteMultipleValues really bahaves. We're using QuickOpc Version "5.70.1053" in a .net6 environment.

I do not want my whole application to stop while we are trying to write to the OPC Server. So we use a similar approach as you described here (www.opclabs.com/forum/ua-reading-writing-subscriptions/2451-...is-synchronous-or-asynchronous). But Unfortunatly when we are calling WriteMultipleValues from different Tasks (Threads) WriteMultipleValues does not keep the sequence.
e.g.
Step 1 call WriteMultipleValues for 3 bool Items setting all to false. Lets call those items A, B, C
Step 2 while the first WriteMultipleValues is still active, we're trying to use WriteMultipleValues to A to true

Unforturnatly both calls will return succes, but the second call will return first. This will result in a "lost update".

Questions:
1. Is this behaviour intended?
2. Is there a different part of the API that we can use to get both, "sequential writing" and "not blocking our application"?

If not we will need to implement kind of a message queue in our own code. But therefore we need some information.
3. Is there any kind of "cache" inside the Lib?
4. When calling in a scenario when the OPC-Server is not reachable, will the value be written as soon as the the OPC-Server is reachable again?
5. When calling WriteMultipleValues in a scenario when the OPC-Server is not reachable, a call will take between 100ms and 2000ms. Where does the big difference come from?