UV Sensor FAQs

Which UV Sensor model do I need?
All UV sensors use the same detector. The model number you need depends on which output is compatible with your datalogger. Model numbers are listed below with their output:
SU-100 0 to 40 mV
SU-420 USB/software
MU-100 Sensor integrated into top of handheld meter with digital readout
MU-200 Sensor attached to a handheld meter via cable with digital readout
Does the UV sensor measure UVA, UVB, and UVC? Can I get readings from just UVA or just UVB?
The UV sensor will detect all UVA, UVB and some of UVC, providing an integrated total of UV A, B, and some C radiation as one value. The UV sensor is sensitive to wavelengths from 250 nm to 400 nm. UVA is 315 to 400 nm, UVB is 280 to 315 nm, and UVC is 100 to 280nm. See the spectral response graph below.

UV Spectral Response

Is this sensor waterproof?
Unfortunately due to the nature of the way the UV sensor is built it is not waterproof.
Can I add additional cable to my sensor?
Yes, if properly spliced, the signal from the sensor is not affected by splicing on additional cable. We have tested splicing up to 100 meters of cable. For information on how to create a proper waterproof splice, please visit our Instructional webpage or watch our video.

We offer custom cable lengths of our high quality cable and splice kits that can be ordered at the time of purchase.

Do I need to order a sensor to go with my meter?
No. All Apogee meters (MO, MP, MQ, and MU series) either have sensors built into the meter or attached via two meters of cable. If you order a sensor only (SI, SO, SP, SQ, and SU series) you will need to have your own datalogger (or, depending on the sensor, a voltmeter) to collect information form the sensor.
Can I add cable to my meter?
Although it is possible to splice additional cable to the separate sensor, note that the cable wires are soldered directly into the circuit board of the meter. Care should be taken to remove the back panel of the meter in order to access the board and splice on the additional cable, otherwise two splices would need to be made between the meter and sensor head. Click here for further details on how to extend sensor cable length.
I received an error code on my meter. How do I fix it?
Error codes will appear in place of the real-time reading on the LCD display and will continue to flash until the problem is corrected. For steps on completing a fix please refer to the manual.
Err 1: Battery voltage out of range. Fix: replace CR2320 battery and perform master reset.
Err 2: Sensor voltage out of range. Fix: perform master reset.
Err 3: Not calibrated. Fix: perform master reset.
Err 4: CPU voltage below minimum. Fix: replace CR2320 battery and perform master reset.
What kind of battery does my meter take?
The meter takes a CR2320 coin cell battery.
What should I do if my meter becomes non-responsive or experience anomalies?
A master reset can be performed that may correct the problem. *Note: a master reset will erase all logged measurements from memory.

First press the power button so that the LCD display is activated. While still powered, slide the battery out of the holder, which will cause the LCD display to fade out. After a few seconds slide the battery back into the holder. The LCD display will flash all segments and then show a revision number. This indicates the master reset was performed and the display should return to normal.

Is each logged or sampled reading time stamped?
No they are not– user should record the starting time when the meter is placed in LOG mode and take note of time when sampled readings are taken.
How many readings will the meter take in LOG mode?
When in LOG mode the meter will power on/off to make a measurement every 30 seconds. Every 30 minutes the meter will average the sixty 30 second measurements and record the averaged value to memory. The meter can store up to 99 averages and will start to overwrite the oldest measurement once there are 99 measurements. Every 48 averaged measurements (making a 24 hour period), the meter will also store 99 integrated daily totals in moles per meter squared per day (mol m-2 d-1).
How many measurements can I take in SMPL mode?
When in SMPL mode press the sample button to record up to 99 manual measurements (a counter in the upper right hand corner of the LCD display indicates the total number of saved measurements).
My USB sensor is no longer working after performing an automatic update. How do I fix this?
Please email techsupport@apogeeinstruments.com with the model number and serial number for your sensor.