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05-17-2011 11:28 AM
Hi All ,
I'm trying to write a VI in the labview 8.1 version for testing sensors. The power to the sensor is pulsed And I need to get a value when the power to the sensor is ON and power to the sensor is OFF ( measure Max voltage when current is passing through the circuit and min voltage when no current is passing through) . My cycle is like 2 seconds ON and 8 seconds OFF.
And I want to acquire a reading in each of these states continuously. I'm able to use a counter pulse to do the pulsing but how can I tie this up with the data logging so can be sure that I'm logging in one data point in the ON state and one in the OFF state?
Thanks
SJ
Solved! Go to Solution.
05-17-2011 11:55 AM
Acquire the pulse from the counter on an additional analog input channel. When it is high your sensor is ON.
Lynn
05-17-2011 12:38 PM
Thank you , Okie now so I get the pulse in teh input line but How can I make sure that i log in a data point when it is On , so say maybe at at 1.5 sec(after it is ON) and then I want a datapoint in the low time , say like at the 5th second (once its off). so how can I trigger the data acquisition only at these times for every cycle?
05-17-2011 12:39 PM
by data point I mean the sensor response(voltage measurement) at these times.
05-17-2011 01:35 PM
Let's create an example. Suppose you sample each channel 10 times per second. If the pulse goes high at the 17th sample, then log the sensor sample at i = 17 + 1.5 s * 10 S/s = 32. Similarly the off sample would occur 50 samples after the falling edge of the pulse.
The timing is a simple process of sample rate and counting samples.
If your process generates much noise, take a subset of the samples near the time you want to record the data and average them together.
Lynn