Siemens Fault 0a7991 __top__ | LATEST • Tricks |

: If you see both, there is likely a communication issue with the PLC. If no PLC is connected, set P2030 = 0 (No protocol) and perform a RAM to ROM save before restarting.

If no PLC is present, set (No protocol) and perform a power cycle. Troubleshooting Tips How can resolve the alarm Code A7991 - Siemens SiePortal siemens fault 0a7991

To minimize the occurrence of the Siemens fault code 0A7991: : If you see both, there is likely

for performing a RAM to ROM save on a BOP-2 or via STARTER software? How can resolve the alarm Code 7991 and 8526 - SiePortal Troubleshooting Tips How can resolve the alarm Code

As with any complex fault, prevention is better than a panic-driven reset.

Siemens has improved the vapor lock detection logic in firmware versions > 4.7. Update your CU (Control Unit) to avoid nuisance trips.