S7-1500 troubleshooting answers
5 questions with answers cited from the manufacturer manuals.
- 0S7-1500 OB122 I/O access error (16#42) in RUN, what to check?
An OB122 I/O access error on a Siemens S7-1500 CPU indicates a problem during direct access to I/O data, such as reading from an input module. The CPU will remain in RUN and log a diagnostics buffer entry. A 16#42 fault …
- 0S7-1500 CPU in STOP with OB121, Fault_ID 16#3A after partial download, what to check?
An S7-1500 CPU in STOP mode with OB121 and Fault_ID 16#3A indicates a programming error, specifically an attempt to access a data block (DB), function (FC), or function block (FB) that is either not loaded or does not ex…
- 0S7-1500 OB86 Rack Error: PROFINET device keeps dropping off, why?
An OB86 Rack Error on a Siemens S7-1500 indicates a failure or return of a DP master system, PROFINET IO system, DP slave, or IO device. Unlike S7-300/400, the S7-1500 CPU defaults to staying in RUN mode if OB86 is not c…
- 0Siemens S7-1500 CPU in RUN, OB82 diagnostic interrupt, what to check?
An OB82 diagnostic interrupt on a Siemens S7-1500 CPU indicates a change in a diagnostics-capable module's status, a power supply/battery backup error, or a memory error. Unlike older S7 models, the S7-1500 CPU remains i…
- 0Siemens S7-1500 OB80 Time Error: Cycle Time Exceeded, what to check?
An OB80 Time Error on a Siemens S7-1500 CPU means the cyclic program or an interrupt OB ran longer than the maximum configured cycle time. While the CPU continues after the first overrun with OB80 present, a second overr…