Device non able to connect after deleting and recreation

Ignition
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1

Hello, and thank you in advance for your help.

On an Ignition Gateway, I created a device connection to a PLC by entering only the device name and IP address.

The PLC showed a “Connected” status, and in the Designer I created a tag that correctly read a memory area and displayed the value at runtime.

After a few weeks, I realized that the PLC had been configured as a “Siemens S7‑300” device, while the actual PLC model is an S7‑400.

I then deleted the device from Ignition and recreated it using the same name and IP address, this time selecting “Siemens S7‑400” as the device type.

However, the device remained disconnected, and I was never able to get it to connect again.
I also tried deleting and recreating the device multiple times, both as S7‑400 and S7‑300, but it never reconnected.

As a result, the tag in the Designer (which I never deleted) now shows an error.

My question is:
Is there any Ignition setting I should check, or any kind of caching (possibly related to the existing tag or device configuration) that could prevent the device from being recreated and connecting correctly?

From a network perspective, the PLC is always online and reachable, and there are no firewall or communication blocks between Ignition and the PLC.

Any suggestions would be greatly appreciated. Thanks in advance.

2

Browser auto-fill and simple copy/paste errors can cause this.

Check for extra spaces, or just type in the configuration manually.

1 Like
3

Thank you Duncan, but is not that type of error.
We checked (and entered manually) all the fields (in the end only the IP address is the basic one) and the problem is not that…
Is there a way to understand with certainty which issue is blocking the connection to the PLC (that previously was working without any issue)?
Maybe with logs, but I am not able to get more info through them:

ConnectRequest 19Mar2026 14:52:40 ConnectRequest failed. FailureType: DISCONNECTED

java.lang.Exception: RequestCycle stopped.
at com.inductiveautomation.xopc.driver.api.BasicRequestCycle.shutdown(BasicRequestCycle.java:278)
at com.inductiveautomation.xopc.driver.api.AbstractDriver.createNewRequestCycle(AbstractDriver.java:698)
at com.inductiveautomation.xopc.driver.api.AbstractDriver.notifyConnectionLost(AbstractDriver.java:682)
at com.inductiveautomation.xopc.driver.api.AbstractSocketDriver$DriverIOEventHandler.connectionLost(AbstractSocketDriver.java:278)
at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.reportExceptionAndStopRunning(AsyncSocketIOSession.java:146)
at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.run(AsyncSocketIOSession.java:87)
at java.base/java.lang.Thread.run(Unknown Source)

AND

NegotiatePDURequest 19Mar2026 14:52:40 NegotiatePDURequest failed. FailureType: DISCONNECTED

java.lang.Exception: RequestCycle stopped.
at com.inductiveautomation.xopc.driver.api.BasicRequestCycle.shutdown(BasicRequestCycle.java:278)
at com.inductiveautomation.xopc.driver.api.AbstractDriver.createNewRequestCycle(AbstractDriver.java:698)
at com.inductiveautomation.xopc.driver.api.AbstractDriver.notifyConnectionLost(AbstractDriver.java:682)
at com.inductiveautomation.xopc.driver.api.AbstractSocketDriver$DriverIOEventHandler.connectionLost(AbstractSocketDriver.java:278)
at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.reportExceptionAndStopRunning(AsyncSocketIOSession.java:146)
at com.inductiveautomation.iosession.socket.AsyncSocketIOSession.run(AsyncSocketIOSession.java:87)
at java.base/java.lang.Thread.run(Unknown Source)

4

Please don't post screenshots of code or error traces. Post them, complete, as text, and apply the forum's Preformatted Text styling.

Based on what is visible, you will need a wireshark capture collected at the Ignition gateway, preferably with a capture filter like host 10.20.30.40, where you use the target IP in place of 10.20.30.40. My guess is that you have gateway or network firewalls interfering, perhaps after IT updates.

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