申请JEasyOpc订阅

Question

Is it possible to request a subscription of a specific item to a OPC Server using the JEasyOpc library? Using async20Read(Group group) will only subscribe the group to the OPC Server in such a way, that after an event happened all items belonging to the group have to be downloaded at the client side. This costs lots of bandwidth having thousands of items which have to be downloaded if one item drops an event!

Answer 1

I haven't used JEasyOPC, but the OPC specification states that AsyncIO::Read and AsyncIO2::Read accepts a list of items that you want to read from the server. This allows you to specify exactly how many and which items' values are to be sent in an update.