# Scan Classes Showing 125% at 450ms and 18% at 1,000ms **URL:** \ **Category:** Ignition\ **Tags:** ignition79, vision\ **Created:** [June 7, 2023, 7:04pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735 "2023-06-07T19:04:08Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 7, 2023, 7:04pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/1 "2023-06-07T19:04:08Z")
I'm confused on why I am showing 125% at scan class 450ms. I am the only person who has worked in this project and have only changed the default scan class to higher scan classes. I had looked into the default scan class, and online it says that it is 1,000ms so why is my gateway status for this device showing such a high percentage for 450ms? Additionally, I exported the tags into Visual Studio Code and did a search for 450ms and nothing pops up like it does when I search for 3,000ms, as an example. Is there something I am missing? ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [June 7, 2023, 7:06pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/2 "2023-06-07T19:06:52Z")
Can you post a screenshot of what you're looking at? Do you have any Transaction Groups? ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 7, 2023, 7:28pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/3 "2023-06-07T19:28:10Z")
Yes, here is the screenshot: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/e/6efee7ca8bc1a737d4f7ea99f024b7037168f80a.png) I am connected to an OPC server, and the device is a Bradley Allen Logix Driver, but I am only writing to a database on maybe half a dozen tags so far. Does that answer your question on the transactional groups or is there something else that it entails that I'm missing? ---
**Author:** ![dkhayes117](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dkhayes117/32/68344_2.png) [@dkhayes117](https://forum.inductiveautomation.com/u/dkhayes117)\ **Post date:** [June 7, 2023, 7:30pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/4 "2023-06-07T19:30:40Z")
The transaction groups can be viewed on the gateway webpage under `status -> transaction groups` to see if you have any running. ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 7, 2023, 7:34pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/5 "2023-06-07T19:34:34Z")
Thanks! I just checked and I do not have any transaction groups running: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/8/d89868d2162025d97858a3133ce3104fc6c9baaa.png) ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [June 7, 2023, 7:37pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/6 "2023-06-07T19:37:26Z")
If that 450ms diagnostic group survives a gateway restart then it's not a bookkeeping issue and there's definitely _something_ subscribed at that rate. There's really only 3 possibilities: 1. Scan Class 2. Transaction Group 3. Connection from another OPC UA client Maybe you can call support and let them take a look? ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 7, 2023, 7:44pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/7 "2023-06-07T19:44:15Z")
I'll have to give them a call. I just can't figure out where it is coming from because in Visual Studio Code, I can search 1250ms and see the tags: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/f/9f3620d6e69e8c07eca8b0517571174ae96a1440.png) And same for this scan class: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/7/f7580f1d856d19766b5ea1d111e400804feacfcd.png) But nothing for 450ms: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/5/15c8d695bb215fb1eea96bab508d30636331f37b.png) Thanks for the suggestion! I'll see what they say. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [June 7, 2023, 7:50pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/8 "2023-06-07T19:50:13Z")
Have you just opened the scan class dialog in the Designer and looked through each one to verify none of the rates are 450? ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 8, 2023, 12:35pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/9 "2023-06-08T12:35:07Z")
I took your suggestion and looked in the designer at the scan class dialog and none of them have a scan class of 450ms. It doesn't make sense because if anything, the default scan class has the most tags and should be the one over loaded. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [June 8, 2023, 12:41pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/10 "2023-06-08T12:41:52Z")
> [@Kevin.Herron](#): > > 1. Connection from another OPC UA client You need to examine your OPC Server configuration to see if this is possible, and possibly use `netstat` to locate the connection origin if it is. ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 8, 2023, 3:11pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/11 "2023-06-08T15:11:22Z")
I ended up talking with Ignition support. Somewhere along the line, someone had changed the default scan class for the OPC server to 450ms so all of my tags that were set to default, were actually scanning at 450ms. Additionally, it looks like there are over 30,000 tags being scanned at this rate. Support explained how the OPC server does all tags in each scan class at one time, so it was being overloaded. I looked into other projects, and they are also overloaded at this rate, and it makes sense as to why. Hopefully in the future when I begin to work in these older projects to update them, I can fix this and only set the ones needed to scan that quickly. Thanks for all the help! ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [June 8, 2023, 3:13pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/12 "2023-06-08T15:13:12Z")
> [@Brittany\_Villasenor](#): > > I ended up talking with Ignition support. Somewhere along the line, someone had changed the default scan class for the OPC server to 450ms so all of my tags that were set to default, were actually scanning at 450ms isn't that exactly the last thing I suggested you look for? 😕 ---
**Author:** ![Brittany\_Villasenor](https://avatars.discourse-cdn.com/v4/letter/b/e68b1a/32.png) [@Brittany\_Villasenor](https://forum.inductiveautomation.com/u/Brittany_Villasenor)\ **Post date:** [June 8, 2023, 5:33pm UTC](https://forum.inductiveautomation.com/t/scan-classes-showing-125-at-450ms-and-18-at-1-000ms/74735/13 "2023-06-08T17:33:49Z")
Yes? But I apparently did not know how to do it correctly, which is why I ended up having to contact support. I appreciate your help.