We currently use the Ignition-provided OPC-UA server to pull in data from multiple devices via Modbus. Our devices are all microprocessors (arduino based) and in general everything is running very smoothly.
As we expand our deployment and have more potential users we have some concern about possibly overloading these microprocessors.
This is a really simple question but I have to ask: When a client views data on their screen, are they viewing cached data from the OPC-UA server, or is a request being made to pull tag data live directly from the end-point device? In the case of (say) 100 users pulling up data on to 100 screens, does this make any difference at all in terms of what the endpoint device (a microprocessor in our case) is doing?
In other words, if the data is cached on the OPC-UA server, then I would guess it doesn’t really matter how many users are looking at it as the limiting factor is the processing power of our (rather powerful) server. If more users = more calls for data directly from our modbus-connected microprocessors then I’m concerned this would cause them to slow down or lock up.
Any comments here would be appreciated! Sorry for such a basic question!