Applicable Systems
WinCC
Symptoms
WinCC SCADA lost connection to S7 PLC; live data not updating; alarm and trend functions may be degraded.
Possible Causes
- Network cable disconnected
- PLC powered off or in STOP mode
- WinCC connection configuration error
Troubleshooting Steps
- Step 1: Check WinCC connection status in Variable Manager
Connection status shows connected - Step 2: Verify PLC is in RUN mode (RUN LED green)
PLC in RUN mode - Step 3: Check network cable between SCADA PC and PLC
Cable connected and intact - Step 4: Ping PLC IP address from SCADA PC
Ping successful (< 1ms) - Step 5: Restart WinCC connection or restart SCADA runtime
Connection restored, data updating
How to Reset
Restart WinCC runtime or reconnect in Variable Manager.
Frequently Asked Questions
- Q: What is WinCC?
Siemens SIMATIC WinCC is SCADA software for process visualization, alarming, and data logging. Connects to S7 PLCs via PROFINET/PROFIBUS.
Source: Siemens WinCC System Manual
Category: SCADA