I am having issues with my tag groups not polling devices at the correct speed I have set them at.
The rate the tag groups were polling at before were causing heavy network load on the devices so I tried to adjust them to slower rates. But when I change the rates and apply them nothing changes. When I look at the devices details page, they are still being polled at old rates. What could cause the updates to the tag groups to not be recognized by the gateway? I am also fairly new to this, been working on a project for a couple months and it is my first time using ignition so I am still learning and may be missing some things. Any help would be appreciated.
Thanks.
Edit: Solution to the tag group configuration not updating in the gateway for me was to restart the gateway. Restarting the devices did not seem to help anything. I had to do a full gateway restart. It has only happened to me once but if anyone else has this issue. That is what I had to do.
When you overload a device, it runs at the fastest rate it can achieve for the load. You won't see any change at the device until you reduce the load enough for the device to have some free bandwidth.
FWIW, the most common newbie mistake is dragging big chunks of the PLC's tags from the OPC browser over to the Tag Browser. Don't do that. Only make Ignition tags for the PLC tags that you actually need.
Oh yes, I did know not to do that thankfully before I started. I figured the more tags you had in ignition, the more load it would put on each device. I know that part of the issue I have with our setup is we are working with several 20+ year programs that have not been optimized at the device as well so it is already on the slow side. I only have the tags we are actually needing on the screens in ignition for each device so I'm having to try to optimize in other ways the best I can. But are you meaning the actual sampling interval rate is what I will not see change until the device has free bandwidth? What I was meaning was like I have a tag provider with 3 different tag groups set up, depending on whether it's a process variable that needs to be a live active value, a setpoint value that doesn't change that often or a timer value that only needs to poll at a slower rate than the process variables themselves. Those tag groups are set to 1000 ms, 10,000 ms, and 2000 ms, respectively. But when I look at the devices page that are using those tag groups the sampling rates have not changed at all. They are still showing the old tag groups rates as the "Sampled at" rates and are not changing when I update the rates for the tag groups. Those should change when I update the tag groups correct and if it was causing overload it would just show overloaded and be receiving a slow actual response rate right? Or am I thinking wrong there? Just wanted to make sure I was explaining what I meant properly and understanding correctly.
I have done both of those. Tried several different times in different orders. Also tried restarting modules they use to communicate. Also did not change anything. Starting to wonder if maybe a gateway restart is required to get them updating correctly again.
Most of my tags for this project are in one provider. I do have another provider set up for a sub-project that works alongside this project using separate PLC's but those polling rates seem to be correct. These tag groups are set up in my default tag provider. All of the tags I have set up fall under one of these three groups. Also included a screenshot of one of the devices pages that shows sampling rates that are not in any of these tag groups.
Thanks, I have also tried using direct mode but that seems to create a bigger overload on our PLC's. It seems to me almost like it got hung up somewhere and is not updating changes on the gateway for whatever reason. Was going to try a gateway restart next to see if that changes anything.
That one in particular is an automation direct DL450 i believe. Most of our plcs are variants of DL400 series processors and siemens 505 processors. With some sl-1200 processors. If i understand what ive been reading and learning correctly I think part of the issue with why they are so slow is because the programs themselves are not optimized very well and cannot take advantage of request grouping to fetch the tag values. So it makes a lot of single tag requests using more of the bandwidth.
Oy! You are toast. With those response times, you can only handle four requests per second. You might be doing those optimizations sooner than you hoped.
Thats what I was talking about before. Im having to try to optimize the best I can in ignition right now because these programs are 20+ years old and have not been optimized after restructuring on old legacy equipment. So it would probably take a complete rebuild to get the plcs optimized to where they arent being worked to the bone.
Thats basically what I have been relying on, slower poll rates for tags that dont change that often but still need a live value and only polling more frequently on process variables that need to be consistent. They are slower, hoping we get the programs better optimized at some point as well but that will be a future project if ever lol.
Did you figure this out? I am having the same issue, the gateway does not take my configuration on the tag group. I have big PLC but as everything is polling at same rate overload is 150 + %
If overload is anything other than zero, you are simply asking for more data from your device than Ignition can acquire at the pace desired. Full stop.
There are a whole host of possible reasons. You'll need to share your details for us here on the forum to provide any meaningful advice.
If the gateway is not updating your configuration, the only way I got that to take in my case was to restart the gateway and then it started accepting changes again. As far as the overload, just as pturmel said. The overload is a calculation of how much the device is behind in its configured poll rate by percentage. You are simply asking for more data from the PLC than it can handle. Best thing is to remove any tags not actively needed to be used in the client for whatever you are hoping to accomplish. After that if more optimization is required, try setting different poll rates for different tag groups. Since my devices were quite limited in the amount of data they could handle. I personally set my setpoint tags at a much slower rate since they don't change that often, they don't really need to update on the screen very quickly. And then made different tag groups based on how quickly I needed the data to update. If it was a process variable that I needed to see in real time, I set it to 1 second update and for things that we only needed to see if the state changed at some point, I set those a little slower to not be processing so much data at once. But most likely if you have a big PLC and you just pulled everything into ignition. It would probably be best to just remove all the unnecessary tags. Chances are you don't actually need everything in the PLC. If you do need everything then it seems like you are going to have to make some compromises unless you could upgrade the PLC to one that could handle the amount of data you are requesting from it. Also be mindful if there is anything else requesting data from that PLC as that will limit the amount of bandwidth you have available on that PLC to be used with ignition. But again as pturmel said. It's hard to give definite help without having details of your specific circumstance.
