Trigger should not alarm until certain number of data collected

[sage12]

Hello, can you suggest how to create such trigger:
I have an item that gets polled once an hour
I do not want my trigger to be in alarm until I collect n values, or for some time period.
I have tried something like
max(#31)}<0 but it sets alarm already after 1st check.
I have also tried max(5d)<0 also with no luck

any suggestions are much appreciated,
thanks,
Igor.
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