Ignition has OPC-UA driver for Siemens S7-300 device. Is the driver capable to connecting to the Siemens device in Slave (unsolicited) mode? This is so that the Siemens device will be the master and the Ignition app the slave which does not need to poll the Siemens device, but able to respond to the message event from the device.
If the driver is not capable to do so, does Ignition have another driver for doing so?
Take a look at the ‘Generic TCP Driver’ on Github. It is an open source OPC-UA driver for Ignition that supports a passive (server) mode.
This driver is meant to be used for custom protocols without polling.
I have tried your Generic TCP/IP and found it quite good with its configurable incoming packet though the outgoing packet is of but one data type. I will see if I can further make use or learn from it.