I’m working on a project where we have two Ignition installations for a small unmanned water treatment plant. One will be local to the plant, while the other will be in a cloud server. The connection between the two will be through a cell phone modem.
I want to make sure that we use as little bandwidth as possible, so I want to make sure I understand the different connections that will exist and the correct places to limit the polling. I have a connection on the cloud server to the Local OPC UA Server under OPC Connections. Below is a diagram of what I think it looks like:
Connections for local Install: PLC -> Local Ignition OPC-UA Server -> Local Tag Provider -> HMI & Local DB
Connections for cloud Install: PLC 1) -> Local Ignition OPC-UA Server -> 2) Cell Modem -> Cloud Server Tag Provider
I want to be sure that I understand which settings effect which connections. I numbered the connections here.
- is effected by the Subscription Rate setup which can be done in Configure > OPC Connections > Quick Client
- is effected by Scan Classes that I set up in the designer and assign to my tags.
Is that all correct?
I’m planning on using Internal Standard Tag Providers for both servers, because I want the cloud server to have limited control, and to be able to change some things on the tags. Alarming is going to be setup on the same tags from both servers, but only actually sending out those alarms from the cloud server. Also I am going to use Tag Splitting from the Local server to send history to the cloud, so that my realtime tags will only have to poll when a client is open, and so that history will always get to the cloud, even if the cell connection goes down briefly.
Is there anything I am doing wrong, or are there other possibilities I should consider?