KepServerX - Device is not responding. Connection closed by device

[MT_10418456]

We are working with PLC Siemens S7-1500 Firmware v4.0. OPC is able to establish connection but at some point it disconnects and gives following error: "Device is not responding. Connection closed by device". Slot and rack in configurtion is correct.

PLC Siemens S7-1500 Firmware v4.0

KEPServerEX version 6.18

Could you please suggest any solution?

[rajskumar]

Hello,
Assuming you're using the Siemens S7 Plus Ethernet Driver — in version 6.18, we added support for S7-1500 devices with firmware version 4.0, so you should be covered in that regard.

I reviewed the manual, and based on the information provided:

• Possible Cause: The device refused the connection due to too many connections.
• Suggested Solution: Verify the number of connections allowed by the PLC.

Kindly check this configuration and see if it resolves the issue. If the problem persists, capturing a Wireshark trace may help us understand what’s happening at the packet level.

Please let me know how it goes. Thanks