Compare Current Value with Old Value for data collected in Real Time

[FermentationGuy]

Hello all,

I am running a fermentation software that uses VBA. I am looking for the script to trigger a response to occur as soon as one of the values drops below it's previously logged value (Example: 1, 2, 3, 4, 2 > Trigger response) (aka the beginning of a negative slope on a curve). This is all real-time values and needs to be triggered as soon as this drop happens.

(Example of the point on the curve I want the response triggered at)

Is there a way to have a script log and save a value, wait a couple minutes, log the same variable again, and compare the current and old values? And do this continuously until the value drops?

Any help would be much appreciated!

 

[Micron]

Should be doable, but not enough info - at least for me. What application is the vba in? Log where, sheet? Doc? Text file? Database table?
Simplest answer might be a module level variable that holds the last value and each time the event fires, the comparison is made.
Or global variable (less attractive option IMO) or TempVars. The value cannot be stored in timer event procedure.