Device is not Responding | ID = ... | Configuration of Tia V15.1 - S7-1200 via PLC sim to Kepware

[Wpadrigon]

Hello Community!

Can anyone give me a clue why does this happen. It worked but after some time it doesn't. See the image below.

I already followed this error solution steps. However, this error still showing up.

The concept is about connection of PLC simulator V15.1 of PLC 1200 to Kepware.

I tried using NetToPLCssim if this the case but still the error persists.

[pshashipreetham · Accepted solution]

Hi, 

Even though your initial setup works, this kind of intermittent failure usually points to TCP connection handling issues, especially with simulators or tunnelling tools like NetToPLCSim.

Here are the most probable root causes:

1. NetToPLCSim TCP port hangs or closes after the idle timeout or multiple reconnects.

2. Too many open/half-open connections between Kepware and the simulator.

3. The Simulator network interface (PLCSim V15.1) may enter an unusual state due to limitations in NetToPLCSim.

4. The Kepware S7 TCP/IP driver retries too quickly after a dropped session, causing repeated connection denials.

5. Windows firewall or antivirus temporarily blocks or throttles simulated interfaces after suspicious traffic.

NetToPLCSim is not production-grade software. It’s best for testing but not for long runtime reliability. If possible, switch to PLCSim Advanced, which offers better support for Ethernet-based communication.

Thanks,