need a function (not macro with ontime) to record a snapshot of a changing cell

[Shannon]

Cell A1 = current time
Cell A2 = time at which I would like a snapshot
Cell A3 = a constantly changing value (like a volatile rand() or a
stock price during the day)
Cell A4 = once the snapshot time is reached, a non changing value
equal to the value of A3 at the snapshot time

I wrote a funtion that worked, but only by using module level
variables. Because this function is called fom many cells, each cell
needed its own variables. This was impractical. Would have needed
2,000 seperate functions.

All other functions i have written with if-then statements return 0
after the current time exceeds the snapshot time.

I know there is probably a simple solution, but my brain is currently
in manual-only calculation mode.

Thanks for the help.

 

[Bernie Deitrick]

Shannon,

You can want a function, but you won't get one. You need to use macros with
ontime to force constant recalculation or you won't have any luck with this.

To help you change your mind, I promise that the macro will work will all
your cells, and not require that each cell have its own variables.

Waiting for your decision,
Bernie
MS Excel MVP

 

[Shannon]

Bernie,

Thanks for the reply.

Last night I created a function with an module-level array variable
(500,6). The funtion dumps a new value to the array if the time is
less than or equal to the target snapshot time, else leaves the array
alone. Then the funtion returns whatever is in the array.

This works, but is pretty slow and is taking up all my cpu processing
power. I guess because the array is updating every time one of the
500x6 values changes (about every second), even after the target time
has been passed.

I'm game to try your macro. Please let me know the next step.

Thanks.
Shannon

 

[Bernie Deitrick]

Shannon,

Assumptions: The time to capture in entered in column B (entered as
time only), the value to capture is in column C, and the captured
value should be placed in column D (which will be empty until the
captured value is place in it). All cells are on the same row, all on
just one worksheet, the active worksheet.

Copy the code below into a module. Run "StartIt" to start, "StopIt" to
stop. Assign the macros to buttons or object for ease of starting and
stopping.

HTH,
Bernie
MS Excel MVP

Option Explicit
Dim NextTime As Date
Dim Running As Boolean

Sub StartIt()
Update
End Sub

Sub Update()
Dim myCell As Range
Running = True
'Check every second
NextTime = Time + TimeValue("00:00:01")
Application.OnTime NextTime, "Update"
For Each myCell In Intersect(Range("B:B"), ActiveSheet.UsedRange)
If myCell.Value < Time And myCell(1, 3).Value = "" Then
myCell(1, 3).Value = myCell(1, 2).Value
End If
Next myCell
End Sub

Sub StopIt()
If Not Running Then Exit Sub
On Error Resume Next
Application.OnTime NextTime, "Update", schedule:=False
Running = False
End Sub