What tests can I do in the field or in my lab to test the functionality of my ECO-PAR? Can I calibrate or validate my readings by myself?
The ECO-PAR, due to the nature of PAR sensors, cannot be accurately calibrated outside of the Sea-Bird facility. However, there are some functionality tests that can aid in pre-deployment. A bright flashlight can validate whether the instrument sees light at all.
On a bench test one should see between 1000-4000 counts normally with the instrument in the white cap standing up on the benchtop. Use a terminal program to see the raw counts, such as Tera Term, and point a flashlight beam near the white cap. Doing so with a functioning unit will cause the counts to go to approximately a couple of thousand in a hair trigger fashion. It should be possible to decrease the counts on a properly functioning instrument by cupping ones hands around the white cap to shield it from light. It should be easy to get a response of a couple of hundred counts total in doing this. In the field if you shine a flashlight beam directly into the optics will see low level ambient light and it is easy to regulate the output in counts at the low end of the range (less than 1000 counts) when it is functioning normally. If your unit is not properly functioning, it will go from 50-ish to a couple of thousand counts and it will be very difficult or impossible to get an output of a couple of hundred counts. While the ranges of the response may differ between PAR models, these tests can be used with other PAR sensors to verify operation.