For an example 3 lifts are in grouping out of 6. 1st sets (ABC) are stopping at basement GF1F,2F,3F,4F&8F and remaining lifts(DEF) are restricted with basement ,GF,5F,6F&7F alone.
All the lifts are being run as per the simplex system of grouping / operated in a multi tenanted it single stand alone building.
During peak hour half peak hours lift F got travelled automatically to 8F level
A bit surprise that the lift does not go to 8F level since disabled by grouping chord if suppose over travelled may happen any worst case scenarios. This case has not a over travelled.
After long exercises done by in house team found its a deciding error in the mother board of lift.
Oem also surprised to see this sensational issue and frequent complaints raised by tenants no clue on this. After that, oem changed all the grouping chords mother board few drives n controllers but frequency of issue was reduced but once a day it’s happening
Now under R&D observation