# Impact of UDT usage on performance **URL:** \ **Category:** Ignition\ **Tags:** ignition81, perspective\ **Created:** [November 2, 2022, 10:48am UTC](https://forum.inductiveautomation.com/t/impact-of-udt-usage-on-performance/65987 "2022-11-02T10:48:08Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Frederic\_Avet](https://avatars.discourse-cdn.com/v4/letter/f/f4b2a3/32.png) [@Frederic\_Avet](https://forum.inductiveautomation.com/u/Frederic_Avet)\ **Post date:** [November 2, 2022, 10:48am UTC](https://forum.inductiveautomation.com/t/impact-of-udt-usage-on-performance/65987/1 "2022-11-02T10:48:08Z")
Hello, I'm looking to utilize UDT's for implementing alot of Valves, Motors, Analog sensors,.... Lets say we have a UDT of the following structure: Motor Struct - Cmd Struct - Fwd Bool - Rev Bool - Status Struct - Standstill Bool - Forward Bool - Backward Bool The way I look at it currently with some research on the forums and the web you have the following options: You make an udt with the full UDT subscribed and save this in a Meta data Tag named Source and some parameters with the OPC Path looking like this: - nsu=[http://www.siemens.com/simatic-s7-opcua;s=](http://www.siemens.com/simatic-s7-opcua;s=)"{DB Name}"."{InstanceName}" Then you make the struct of the UDT like you have in the PLC and get each value from the JSON in derived tags with - Source Tag Path: [.]../../Meta/Source - Read Expression: JsonGet({Source},"Cmd.Manual."+{TagName}) - JsonSet({Source},"Cmd.Manual."+{TagName},{Value}) The other possibility is just making the structure and adding the OPC path to each component. This makes a subscription per member of the UDT -\> Not optimal for big UDT's? I'm currently testing the first option but I can't seem to be able to get the tags out of the Leased state when there are no views or clients open. So my questions are these: - Is it possible the setup with JSON read and write interferes with the Leased setting of Tag Group? - What would the most optimal way be to config the UDT's with JSON or OPC UA directly for each member of UDT? - When making template views in perspective i'm currently using path binding as it seems more optimized for big amounts of templates in a view, is this correct? - Do you need to watch out for limits with the Tagproviders and Tag groups? Should you make a new one per x Tags? ---
**Author:** ![Frederic\_Avet](https://avatars.discourse-cdn.com/v4/letter/f/f4b2a3/32.png) [@Frederic\_Avet](https://forum.inductiveautomation.com/u/Frederic_Avet)\ **Post date:** [November 8, 2022, 8:22am UTC](https://forum.inductiveautomation.com/t/impact-of-udt-usage-on-performance/65987/2 "2022-11-08T08:22:00Z")
I have indeed found the answer that using derivative tags to read a document tag will make it impossible to use leased tag groups. Any other additions would be appreciated ---
**Author:** ![m.pelagatti](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/m.pelagatti/32/68595_2.png) [@m.pelagatti](https://forum.inductiveautomation.com/u/m.pelagatti)\ **Post date:** [November 8, 2022, 9:16am UTC](https://forum.inductiveautomation.com/t/impact-of-udt-usage-on-performance/65987/3 "2022-11-08T09:16:13Z")
Hi, read this post > [@Opc and Leased Tag Group](https://forum.inductiveautomation.com/t/opc-and-leased-tag-group/55655): > > Hi to everyone! I have a problem with Opc Ua and Leased Tag Group. Inside my project I have too many tags with OPC (about 2900 tags) and this cause the tag quality to be “Good\_Overload” when the system drop the scan frequency to ensure the readability of all the tags. I would like to know if there’s some way to decrease temporarily the scan frequency of the Opc Tags. I have tried to use the the leased tag group in order to slow the update of hidden tags, but it doesnt work: I see the tag updatin… is not possible to use derivative tags to read a document and use leased tag group, because each derived tag request information to document tag , and is the same like it's showed in a page. I'm in testing another tag group but driven, and request tag only with a bit (for me it's a cycle.started) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/f/2f8e8e7e2fc36ede1012557eac9b5f3ba981f807.png) i use this group in document tag and all tag connected to this cycle. When bit is on , refresh is 1500ms, when is off refresh 3000ms Tell me if is useful for you.