Hi,

A customer of ours have a 1511C-1 PN commisioned by us, and it's been running for a year and a half now, but this morning it went into STOP, then showed a serious firmware exception, restarted a few times and had its memory reset. All DB values were set to start values.

According to maintenance personnel, no one was in the vincinity of this CPU at the time of error. It had to be manually set to RUN again.

We're not sure what could cause this, maybe fluctuations on the 24V DC? Scary that the CPU wiped itself during this, and weird to see the diagnostics say the first STOP and the memory reset was initiated from the panel.

Any ideas of what could cause this?

Here's the diagnostics data from the first event at 6:05 am. No personnel was on site until 06:58 am [attached]

Compare the actual PLC firmware with the latest available firmware.  If there is newer firmware available, check the change logs for all interim firmware updates.  There may be an entry in the changelog like this: "fixed PLC stop with firmware exception".

If there is, then please do get that firmware installed.  There is no need to update the PLC project to benefit from the updated firmware.  Just having the latest firmware installed is the fix.

ostlar

Hi,

A customer of ours have a 1511C-1 PN commisioned by us, and it's been running for a year and a half now, but this morning it went into STOP, then showed a serious firmware exception, restarted a few times and had its memory reset. All DB values were set to start values.

According to maintenance personnel, no one was in the vincinity of this CPU at the time of error. It had to be manually set to RUN again.

We're not sure what could cause this, maybe fluctuations on the 24V DC? Scary that the CPU wiped itself during this, and weird to see the diagnostics say the first STOP and the memory reset was initiated from the panel.

Any ideas of what could cause this?

Here's the diagnostics data from the first event at 6:05 am. No personnel was on site until 06:58 am [attached]