Applicable Systems
KTP700 Comfort
Symptoms
TIA Portal HMI device diagnostics shows red 'PLC connection' icon with error 0x8001.
Possible Causes
- Profinet cable interrupted or industrial Ethernet switch port disabled.
- HMI connection configured with wrong S7-1200/1500 slot or rack number.
- Firewall or IP filter on the PLC blocking HMI connection requests.
Troubleshooting Steps
- Step 1: Check Profinet cable LEDs on both HMI and PLC Ethernet ports.
Both ports show solid green link LED and flashing yellow activity LED. - Step 2: Open TIA Portal, verify HMI connection 'Access point' and PLC IP address.
Connection parameters match the online PLC hardware configuration. - Step 3: Use Siemens Primary Setup Tool or ping to verify IP address reachability.
HMI and PLC are on the same subnet with <1 ms response time.
How to Reset
Restart the HMI panel and trigger a reconnection from the TIA Portal runtime loader.
Source: Siemens KTP700 Comfort Operating Instructions
Category: HMI