Zabbix: Get previous value of item to the trigger operation data

Existing item item-a in Item prototypes in Discovery rule has "Update interval" - 10m.

Create new "calculated" item based on item-a, for example with name item-a-prev. Formula for item-a-prev should by like:

last(//item-a[foo,"{#BAR}"],#4)

Set not long values for "History storage period" - 1d, and "Trend storage period" - 7d, or switch to "Do not keep trends"

In Trigger Expression use:

(avg(/Template_A/item-a-prev[foo,"{#BAR}"],30m)-avg(/Template_A/item-a[foor,"{#BAR}"],30m))>=1

Trigger Operation data:

Delta: {ITEM.VALUE1} -> {ITEM.VALUE2}