# How does the OPC-UA driver determine if it is connected?

**URL:** <https://forum.inductiveautomation.com/t/how-does-the-opc-ua-driver-determine-if-it-is-connected/2081>\
**Category:** Ignition\
**Created:** [July 26, 2010, 8:04pm UTC](https://forum.inductiveautomation.com/t/how-does-the-opc-ua-driver-determine-if-it-is-connected/2081 "2010-07-26T20:04:06Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jgreenewv](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@jgreenewv](https://forum.inductiveautomation.com/u/jgreenewv)\
**Post date:** [July 26, 2010, 8:04pm UTC](https://forum.inductiveautomation.com/t/how-does-the-opc-ua-driver-determine-if-it-is-connected/2081/1 "2010-07-26T20:04:06Z")

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Trying to run down a communications issue, and I came across something I wanted to clarify. I have a machine running a KEPServerEX v4 driver connected to a PLC. I also have a device set up in the OPC-UA driver connected to the same PLC. I am having some communications dropouts with this PLC that have nothing (I think) to do with the drivers, but it has brought something to light. If I have my project using the OPC-UA driver, it will occasionally disconnect then reconnect. I am also seeing this behavior in the KEPServer. However, if I delete the tag using the OPC-UA driver, it never shows disconnected.

So, now that I’ve explained all that, I’ll come to my question. Does the OPC-UA driver occasionally go out and verify the connection to the device, or once it does the initial connection, does it assume the connection is still alive until a communications error occurs?

Thanks.

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**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:** [July 26, 2010, 10:03pm UTC](https://forum.inductiveautomation.com/t/how-does-the-opc-ua-driver-determine-if-it-is-connected/2081/2 "2010-07-26T22:03:25Z")

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What you are probably seeing is a read on the driver that is timing out 3 times in a row. When this happens the driver will disconnect and then reconnect.

When you delete the tag you always see the driver state as CONNECTED because there isn’t actually anything going on.

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**Author:** ![jgreenewv](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@jgreenewv](https://forum.inductiveautomation.com/u/jgreenewv)\
**Post date:** [July 28, 2010, 12:32pm UTC](https://forum.inductiveautomation.com/t/how-does-the-opc-ua-driver-determine-if-it-is-connected/2081/3 "2010-07-28T12:32:29Z")

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OK, that’s what I was thinking, but I wanted to make sure my observations were correct. Thanks.