Looking for some advice as I am having intermittent communication problems with my PLC.
PLC: Allen Bradley 1756-L74, 1756-EN2T Ethernet card. Firmware v20.
This system is development, with little overhead other than background processes and communications to Ignition. Not talking to any IO points, or running any programs. Just enough to interact with the Ignition project. This is in our office on an isolated network so there shouldn’t be any influence there.
Using the Ignition OPC-UA Driver for ControlLogix communications.
The system is running on Windows Server 2012 Essentials R2.
Currently there is a a single Scan Class, setup as “leased” with the slow rate = 5,000 ms and the fast rate = 1,000 ms. I also have a “historical” scan class but right now it’s not logging any data points.
The “fast” rate currently has 11,457 items on scan.
The “slow” rate currently has 58,824 items on scan.
These numbers change obviously with the screens that are open in Ignition due to the “leased” nature, but the “fast” will increase as I add clients to the system. Initially I will have 5 clients, each could be on different screens, thus my “fast” rate tag count will increase. I’m concerned that I am already seeing intermittent communications issues. I don’t feel that I’m asking to much of the system, but maybe I am? This project will also be talking to a 2nd PLC, a CompactLogix in the short future, so more tags will be required. 85,000 total tags is realistic, more in the future as this is just “Phase 1” of this project.
The number of tags I have is “bloated” due to them being BOOL tags for status/configuration of my deices, relates to a feature request thread I created: http://inductiveautomation.com/forum/viewtopic.php?f=71&t=12380
How can I eliminate my comm issues? Am I already taxing the abilities of the OPC-UA driver? This is my first Ignition project, so I’m hoping to caulk this up to inexperience and can be pointed in a better direction. I know I can add more scan classes to be “slower” in nature but I can’t imagine 11,000 tags @ 1 second is that taxing, but what about 58,000 @ 5 seconds??