ABB AC 31 Technical Manual page 193

Page 8-4
Diagnosis
Only one error per class is memorized. If more than one error of the same class occurs at the
same time:
Only the first is memorized.
The first error should be acknowledged to allow the following to be read. And so on through
to the last error.
Those following errors which disappear, before the acknowledgment of the first error, are
never signaled.
ABB Control - AC 31
1SBC 260400 R1001-b 06.99