Hello, I'm John Melville
from Vernier Software & Technology,
and I'm going to show you
how to correct the calibration on a PAR Sensor
so that it's more accurate for indoor use.
Now, our PAR Sensor has an apogee sensor head
that comes precalibrated
for outdoor use in sunlight,
but to make it more accurate for indoor use,
you just have to change the slope.
Now, to do that, it's actually quite simple.
So if you go over here to our LabQuest 2,
you can see that the PAR Sensor
is reading around 240 PPFD
underneath this halogen lamp.
Now, to make it just a little bit more accurate,
since this is a halogen lamp,
it's not the sun, I would just tap here
on the meter screen, select Calibrate,
and then go to the Equation tab,
which is located right here.
And you can see right here
I have the slope and the intercept.
Now, all I want to do is reduce the slope
by about 14%, or change it to 430.
Next I'm just going to select OK
to change that slope.
And now we can see that the PAR sensor
is reading a little bit lower
at around 207, 208 PPFD.
Now, if you want to store this calibration
on the sensor so that every time you plug it in,
it actually comes up precalibrated
for use in artificial lights,
that's quite simple as well.
Just tap on the meter screen, go to Calibrate,
and then select the Storage tab.
And right now all I need to do
is say Save Calibration to Sensor,
and then it would be stored.
Now, what's really nice
is if you want to go back and restore it,
all you would have to do
is select Restore Sensory Factory Default,
and then you're using the calibration for outdoor use.
So I'm going to Save the Calibration to Sensor.
And say OK.
And now it's reading 209.
And now let's say I come back a day later
and I unplug my sensor, plug it back in...
It's reading 209, which means
it's calibrated for indoor use.
Let's just verify that by going to the Calibrate screen
and looking at the Equation.
Oh, it's at 430, so it's come precalibrated
for use with electric lights or indoor lights.
And that's it.
For more information about the PAR Sensor
or other sensors from Vernier Software & Technology,
just visit us online at www.vernier.com.