Author Topic: LiCor Pyranometers  (Read 188 times)

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Offline DaleReid

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LiCor Pyranometers
« on: April 08, 2021, 10:01:00 PM »
I am a little confused by LiCor's pyranometer classification.

I have a couple that I've accumulated over the last few years from eBay sales and such.

They almost all have a shielded two wire output, with a short section of red covering exiting over the cable for maybe three inches where it exits the body of the device.

I look at the label, and it says MODEL: and in the white area the (being sarcastic) helpful printing is PYRANOMETER.  Well, duh.

There are serial numbers, some with PY preceding the 5 digit number, which I assume IS a serial number.

My question is, are there are identifying characteristics to tell what KIND of LiCor I have?  There are various model numbers listed on their web site, but not much to help determine what kind I have.

There are some that claim to be a microvolt output for radiation, and others that claim to be 4-20 mA, but some of those appear to have a little device in-line with an outgoing cable attached, at least scanning the various ones listed for sale on eBay for the last few months.

I am wondering if there is ONLY one type, that is the voltage output one, and the 4-20 mA current loop is created by feeding the voltage into this in-line gizmo which does the magic of converting it to a current loop interface?  Or are there some which appear identical to each other, that is the black cylinder with the photosensitive white button on top that has the identical coax out which could be either a voltage out, or a current loop out, with the electronics nestled inside the black cylinder which has the LiCor label on it?

Anyone an expert on this?  I have a few and was going to try testing to see if any could be used in another circuit and I don't want to goof anything up.
Dale
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Offline doubleohwhatever

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Re: LiCor Pyranometers
« Reply #1 on: April 19, 2021, 01:37:07 PM »
If the serial numbers are intact on your units then you can email LI-COR at envsupport@licor.com and they'll be able to send you the exact model numbers and datasheets for the units you have.

The serial number indicates the unit type:
Q: Quantum/PAR
PY: Pyranometer/Solar Radiation
PH: Photometric/Lux

This may not be the case for *all* of their light sensors but all that I've ever encountered have mA output from the actual sensor. Any of the units that have had voltage outputs have had an in-line adapter or an adapter that connects to a BNC connector on the sensor cable. The adapters connected via BNC *are not* interchangeable between sensors.

So generally:

Bare leads or BNC with *no* adapter: mA output
Bare leads but with inline adapter *or* adapter connected to BNC: voltage output

The voltage output will either be "0v to 10v" or "-2.5v to 5v".

I've honestly found LI-COR sensors to be a bit of a hassle and have even killed a couple (sensitive little buggers). If you need NIST traceability then they're worth dealing with. However, for non-critical UV, PAR, and solar radiation needs we've been going with these:
https://www.specmeters.com/weather-monitoring/sensors-and-accessories/sensors/light-sensors/
« Last Edit: April 19, 2021, 01:40:54 PM by doubleohwhatever »

 

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