# Siemens S7 1500 OPC UA UDT with string member **URL:** \ **Category:** Ignition\ **Created:** [December 13, 2019, 2:16pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695 "2019-12-13T14:16:51Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![mohamad.tayara](https://avatars.discourse-cdn.com/v4/letter/m/977dab/32.png) [@mohamad.tayara](https://forum.inductiveautomation.com/u/mohamad.tayara)\ **Post date:** [December 13, 2019, 2:16pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/1 "2019-12-13T14:16:51Z")
Hi I have developed a nested level UDT in s7-1500, the PLC is communicating via OPC UA with the ignition, the communication was working fine for the nested UDT until one string member was added, after that the status turned to BAD for the parent UDTs that contains the UDT with the string member. also when tried to drag the variable from the OPC browser it was recognized as string in opposite to Document ( before the addition of the member), i did try to change the data type in the PLC to wString[10], and String[10] to limit the number but that did not resolve the problem, Moreover the string tag will show correctly if it was exposed directly as an opc string tag in the tag browser. Thanks in advance. ![Ignition](https://us1.discourse-cdn.com/inductiveautomation/original/2X/a/a32a2095b6be0d83bf8fb3172f74be5cb48ebfe5.png) ![S71500_UDT](https://us1.discourse-cdn.com/inductiveautomation/original/2X/2/28a271fdb4ab17d131326f6a605580c84707af98.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:** [December 13, 2019, 2:29pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/2 "2019-12-13T14:29:59Z")
What version of Ignition are you using? ---
**Author:** ![mohamad.tayara](https://avatars.discourse-cdn.com/v4/letter/m/977dab/32.png) [@mohamad.tayara](https://forum.inductiveautomation.com/u/mohamad.tayara)\ **Post date:** [December 13, 2019, 2:31pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/3 "2019-12-13T14:31:22Z")
Hi Kevin, i am using 8.0.6 ---
**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:** [December 13, 2019, 2:38pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/4 "2019-12-13T14:38:44Z")
Ok. These problems can be a little tricky to troubleshoot. On Ignition’s logging page there’s an area where you can change the logging level for certain loggers. Search for “DataTypeDictionaryReader” and turn it to TRACE, then edit/save the OPC UA connection to this PLC, and send us the logs after it reconnects. I’ll need to know the name of the all UDTs you’re trying to access here. Also, if you haven’t yet, make sure you do a re-compile and download from the Siemens software. ---
**Author:** ![mohamad.tayara](https://avatars.discourse-cdn.com/v4/letter/m/977dab/32.png) [@mohamad.tayara](https://forum.inductiveautomation.com/u/mohamad.tayara)\ **Post date:** [December 13, 2019, 3:50pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/5 "2019-12-13T15:50:33Z")
Hi Kevin, the problem was resolved, the issue was caused by turning off the accessible from OPC UA / HMI option for wIdent variable in Siemens, once enabled everything went fine, also the writable option should be enabled on all variables since if removed on only one member the whole udt would not be writable in ignition ( probably a siemens OPC UA bug?). Thanks for your support! ---
**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:** [December 13, 2019, 4:16pm UTC](https://forum.inductiveautomation.com/t/siemens-s7-1500-opc-ua-udt-with-string-member/30695/6 "2019-12-13T16:16:13Z")
Ooops, I should have spotted that. All UDT members need to be accessible from HMI and all writable if you’ll be writing to any member.