Alarm triggered when one of the conditions is exceeded

[rltsv]

Hi!
I work with edgex and i need create a rule which will generate alarm in case value exced some reference value.
For example. I have modbus device, it has register with value which goes from 0 to 10000.
I need have 4 boundary conditions:
when value pass from greater then 2000 to lower - send notification like «CRITICAL»
when value pass from greater then 4000 to lower - send notification like «WARNING»
when value pass from lower then 8000 to greater - send notification like «WARNING»
when value pass from lower then 10000 to greater - send notification like «CRITICAL»

I wonder how you would propose to make such a decision, especially the creation of a rule.
And what if there will be much more registers to control by ekuiper, for example 20k different registers, with unique boundary values, should it be one rule to one register or one to many?

[ngjaying]

Something like: SELECT CASE WHEN lag(yourField)<=2000 AND yourField < 2000 THEN "critical" WHEN lag(yourField)>=4000 AND yourField < 4000 END as alert FROM xxxStream