I have a new installation with a Moore / Siemens 353 controller using Modbus TCP. It all works great for the first 15 or so minutes - then, it just times-out and cycles from connecting/disconnecting/etc.
If I disable/enable, it starts to work again - for 15 minutes. Is there some obvious setting that I can change to correct this behavior?
Have you set up some tags yet? It is common for Modbus TCP devices to cut off idle connections. (Sometimes in as little as ten seconds.)
Yes, I have 4 tags configured. The opc quick client at a 1000ms refresh updates without issue... until about 15 minutes... sometimes shorter..
Maybe you can get a Wireshark capture of an entire cycle of this, from connect until it stops responding, but I'm not sure how much help it will be. Sounds like this device is buggy/broken.
So... looks like the Modbus/TCP transaction identifier counts up to 1024 - and, then, poof. I don't think these devices like anything over 1023. Is there some sort of way to make ignition start over at 512 or 1023?
Also referenced here... I/A Series G3 Modbus TCP communications to Siemens Moore 353 controller stops updating after a period of time after ENC/JACE ... - Schneider Electric Community
There’s no configuration for this, no.
So, the options are 1) don't use ignition 2) replace all 353s with something else 3) find an OPCua that would support it or 4) use the SDK to write my own driver?
I suppose I could make an option for this in my alternate driver.
You add, I'll buy. 
Phil's driver is a good option as long as you aren't using Edge, which doesn't allow custom / 3rd party modules to be installed.
After ICC. I have a couple other items needing attention in that driver.
This has now been implemented, via a new driver setting.
Also note the announcement over there that this module of mine is now available in Edge.
