How to set a curve-offset in my diagram

[Daniel Schifferdecker]

Hi,

my VI gets values from an analog input in a loop, and draws these
values in my diagram (voltage values).
Now my curve will look like this:

y
|
| _--_
|______---- ----_______
|
|
|___________________x

Before my measurement starts, I have only a line with a certain
y-value (the "basic" voltage) :

y
|
|
|____________________
|
|
|____________________x

Now I want a button "Offset". When I click it, the current
value should be read and stored, and from then
subtracted from my values.
My curve should finally look like that:

y
|
|
|
|
| _--_
|_____----___----____x

My problem is, how can I read the current value (when I click my
button), and then store it as my "offset", to subtra
ct it from my
further values ?

Thanks in advance for your help !
Daniel

[altenbach]

Just store the last value in a shift register, then subtract it from the new data for display.
See attached VI (LV5.1)