Hi all,
I just wanted to see if it's normal for a device to overload this much for a tag count of roughly 2500. I'm not sure how the overload is calculated, but there are devices with more tag counts (>10k) but they have lower overload value which is a bit confusing for me..
All tags assigned to this device are set on a Leased tag group with Leased rate 1000ms and rate at 5000ms and everything else at default. PLC model is AB 5069-L340.
Many thanks in advance!
Is this device on another network in another country? Does it have other systems already polling it?
The response time is pretty bad.
Hi @Kevin.Herron ,
No, the PLC is sitting right in front of me believe it or not. There's only single gateway if that's what you're asking for but the PLC is running one of our machines with other peripheral devices. I'm playing around with with some of the settings on the device like max concurrent requests and they seem to help out a bit but the overload is still at a crazy level..
You might try changing the system overhead timeslice in the PLC to allocate more time for comms.
I don't think the 5069 controllers have overhead timeslices. If I had to guess, they're using PlantPAx AOI blocks, they're using all atomic tags with no UDTs, or they made their own AOIs and they don't have all the tags set to at least read only for external access.
@Kevin.Herron @michael.flagler
Thanks for the input!
As michael mentioned, I don't think there is an option to adjust overhead timeslices on 5069.
None of the AOI's are used on Ignition side (at least not on the client facing application) and everything we pull from the PLC are defined in UDT although they do have a very complex nested structure and all atomic tags are set to read/write for external access.
I'm also seeing a weird outcome where when I make changes to the parameters on connected device, the response time varies from going very fast initially and declining over time to the point where it's almost unusable. I tried restarting the gateway but the symptom continues 
When you say theyr'e complex nested UDTs, how big (in bytes) is your base UDT? Are you reading all/most tags in these UDTs or just some? What do your tag groups look like? Are you doing direct on everything or using leased tags? I've found doing all direct is usually faster because it doesn't add extra load/processing of changing poll rates of tags, but that's just my opinion.
Have you tried testing Phil's driver to see if you get better results? It's a drop-in replacement for the Ignition driver.
Try temporarily increasing the poll rate for your 5sec tag group (to 30sec? 300sec?) to determine how much that tag group is contributing.
