# SLC Bad Quality with more than 16 tags **URL:** \ **Category:** Ignition\ **Tags:** ignition81\ **Created:** [August 31, 2023, 4:54pm UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633 "2023-08-31T16:54:32Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Bryan\_Strauss](https://avatars.discourse-cdn.com/v4/letter/b/a183cd/32.png) [@Bryan\_Strauss](https://forum.inductiveautomation.com/u/Bryan_Strauss)\ **Post date:** [August 31, 2023, 4:54pm UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633/1 "2023-08-31T16:54:32Z")
I am trying to add tags with an OPC connection to an RMC200 Motion Controller with the SLC driver, as this the supported protocol for the RMC200. Tag group details are: Mode=Direct, Rate=1000ms, Data Mode=Subscribed. Values and tag qualities are good until I create more than 16 tags, at this point all the tag qualities turn to bad, tag values turn red, and tags stop communicating with RMC200. What am I doing wrong? ---
**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:** [August 31, 2023, 4:57pm UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633/2 "2023-08-31T16:57:21Z")
It probably means you're addressing a tag that doesn't exist or otherwise results in an error when read. The tags you've configured are likely all read as part of a single request, and once you include this bad tag the entire request fails. ---
**Author:** ![Bryan\_Strauss](https://avatars.discourse-cdn.com/v4/letter/b/a183cd/32.png) [@Bryan\_Strauss](https://forum.inductiveautomation.com/u/Bryan_Strauss)\ **Post date:** [August 31, 2023, 6:42pm UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633/3 "2023-08-31T18:42:35Z")
After some more testing I have found this behaviour. My address map inside the RMC200 motion controller for the tags I want to access start at address F19:0 and end at address F19:255. It seems I can only access tags in a range of 22. For example: - Tags F19:0 to F19:21 all work, but if I also try to access F19:22 then they all fail. - Tags F19:1 to F19:22 all work, but if I also try to access F19:23 or F19:0 then they all fail. - Tags F19:2 to F19:23 all work, but if I also try to access F19:24 or F19:1 then they all fail. Is there a driver limitation to SLC driver on the ignition trial period? ---
**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:** [August 31, 2023, 6:44pm UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633/4 "2023-08-31T18:44:45Z")
Not that would result in this behavior. Maybe you can get some Wireshark captures. Something like one capture while successfully reading F19:0 - F19:22, another capture where you've added F19:23 and it starts to fail. ---
**Author:** ![Bryan\_Strauss](https://avatars.discourse-cdn.com/v4/letter/b/a183cd/32.png) [@Bryan\_Strauss](https://forum.inductiveautomation.com/u/Bryan_Strauss)\ **Post date:** [September 1, 2023, 3:09am UTC](https://forum.inductiveautomation.com/t/slc-bad-quality-with-more-than-16-tags/78633/5 "2023-09-01T03:09:58Z")
I think I solved this. In my connection path for the SLC Driver I had to put a 1, since on this RMC200 it looks like the cpu is in slot 1. This forced the slc connection protocol to Bridged\_EIP which is now working with all my tags.