# OPC UA Connection to S7-1500 **URL:** \ **Category:** Ignition\ **Created:** [December 22, 2016, 3:01pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500/12493 "2016-12-22T15:01:08Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![andrea.minu](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/andrea.minu/32/3326_2.png) [@andrea.minu](https://forum.inductiveautomation.com/u/andrea.minu)\ **Post date:** [December 22, 2016, 3:01pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500/12493/1 "2016-12-22T15:01:08Z")
Hi Kevin You have wrote that you have tested the OPC UA server built in Siemens 1500 PLC.( TIA v 14) I’m testing now the communication with Ignition v 7.9.0 and I have strange behaviours. If I read a tag with the a scanclasses definited as type OPC DATA MODE= Read, Ignition is able to read the value and every change. But If I set the scanclass as type OPC DATA MODE= subscribed ignition does not reads the change of values best ---
**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 22, 2016, 3:24pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500/12493/2 "2016-12-22T15:24:44Z")
Can you turn the logger “opcua.client.OpcUaConnection.UaSubscriptionChangeListener” to DEBUG and see if any new messages appear in your logs after that? ---
**Author:** ![andrea.minu](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/andrea.minu/32/3326_2.png) [@andrea.minu](https://forum.inductiveautomation.com/u/andrea.minu)\ **Post date:** [January 9, 2017, 10:25am UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-to-s7-1500/12493/3 "2017-01-09T10:25:19Z")
Hi Kevin I solved the problems , doing a upgrade of the firmware of the S7 1500 PLC Best regards Andrea