PtbyPt editing with global variable?

Hey guys,
I'm wanting to setup a counter to count a crossing of a sinewave. The thing is, the sinewave is not zeroed. It's a sinewave of a cyclic load cell that I'm testing a material with. With this test, I will put load on the load cell, then cycle from that position, which is my realitive zero.
So, say I put 0.043 volts on the load cell. I would then cycle the material at a certain strain both ways horizontally, and this "0.043" would be my zero for the crossing. I've included my Vi so you can see what's happening in the "strain" and "stress" state. These states are independant from eachother and don't work together in anyway. They're just recording data on different channels
Is there a way I can edit the Pt2Pt vi to look at this "0.043" value (which is an analog channel)? I was thinking global variable...or...something simpler I could put in my code. I'm still a novice in all this and I would greatly appreciate some advice.
Kindly
Gary S.
Attachments:
New CSS state44.vi ‏405 KB

glskinner wrote:
The signal is crossing at the offset, but my "cycle count" is crossing at zero since I'm using Pt2Pt. How to I get my cycle count to cross at the offset? Is there a way I can edit the Pt2Pt to look at my beginning load cell reading zero/offset (I have it a TTL that starts the data aquisition) and then increment everytime is reaches the offset?
As for the why I need to worry about where the cycle count crosses: I am recording the cycle count as a scalar numeric value in my data file, along side my load cell. I need this cycle count to match with the crossing of the load cell for data reduction purposes. So if the load cell crosses at -0.043, I need the cycle count to change when the load cell crosses that value. I understand the Pt2Pt crosses at zero, but the stipulation for the crossing of this vi, "0", is what I want to change. I want it to cross at my offset (-.043, or whatever the case may be), since that is my true "zero" in relation to the behavior of my load cell voltage.
I think you're not following my train of thought. What you want to do is make a copy of the data (i.e, create a wire branch). On one branch, you will do the crossing calcs. On the other branch, you retain the actual data. On the crossing calcs branch, you will subtract out the offset so you can use the Pt2Pt without modifications. On the other branch you have your original data. There should be a direct correlation between the two. You should now have a record of both how many times it crosses and where it crossed.
Bill
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My support system ensures that I don't look totally incompetent.
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