LPM Help

[NightExplorer96]

Hi. might have to be calibrated reset to zero possibly. Just a hunch thats what it sounds like to me any way. Buti could be wrong or right good luck hey i wouldn't worry to much with that minor fluctuation just deduct the overage mW at the end of your test.. Best to you and your new LPM at least you have one buddy a lot of folks don't have that advantage.

sorry Arg scrolled down past your comment same same )

Thank you for the advice Lifetime17. I'll just deduct the mW's from my laser when testing them as that seems to be the easiest way to enjoy this LPM

-Alex

 

[TaterMay]

What's the range that this LPM is capable of?

 

[MarioMaster]

With the radiant alpha you can actually adjust an internal zero without affecting the calibration of the meter.

To adjust the internal zero follow these steps:
1 put the external zero knob in the center position
2 open the meter and find the adjustable potentiometer marked 101 on top
3 with the sensor isolated from any heat /cold sources, adjust the internal potentiometer until the display reads 0.000

 

[NightExplorer96]

What's the range that this LPM is capable of?

Range is 1mW-2W's :yh:

@MarioMaster

Thanks! I may have to give that a try later today. I won't run the risk of damaging anything correct?

-Alex

 

[MarioMaster]

The resistor marked 101 is the main zero, the other is the gain and should not be adjusted so make sure you have the right one before going at it

 

[NightExplorer96]

The resistor marked 101 is the main zero, the other is the gain and should not be adjusted so make sure you have the right one before going at it

Ok, I have the LPM opened but can't see anything with "101" marked next to it.

Are you sure there should be one on this model? Is it behind the LCD?

Edit: I think I found something with "101 M" next to a screw it looks like. Unfortunately there is a layer of glue on top of it. Should I try to pierce it?

-Alex

 

[MarioMaster]

If glue is covering both potentiometers I'd try to cut the glue and then peel off the glue only on the zero pot side.

 

[NightExplorer96]

If glue is covering both potentiometers I'd try to cut the glue and then peel off the glue only on the zero pot side.

Meh, I'll just use add/deduct the readings I get from the LPM when it shows the output.

Are these kinds of LPM's unreliable at lower powers? Somehow my 520 metered at 1mW

-Alex

 

[Pi R Squared]

Meh, I'll just use add/deduct the readings I get from the LPM when it shows the output.

Are these kinds of LPM's unreliable at lower powers? Somehow my 520 metered at 1mW

-Alex

Yes they are, most of the hobbiest quality LPM's become unreliable below about 20mW. Be careful as I said and be sure the air is still, no fan/AC/heater/open window, and no heat source near the sensor, not even your hand, and you may or may not get a reliable reading. Measure from a distance of 4-8 inches. I doubt it will work on that meter though at such a low power. There are some LPM's you can buy that are specifically made for low power lasers.

Alan

 

[ARG]

Are these kinds of LPM's unreliable at lower powers? Somehow my 520 metered at 1mW

All thermal LPM's perform poorly at low powers, even the Ophir heads are only rated to a 20mW minimum. It's the nature of the sensor, any changes in the environment will affect the reading, if you so much as sneeze in the wrong direction you can throw off the reading by a few milliwatts (no joke).

 

[Gadget]

Arg is right. A strong exhale toward the sensor of my X4 sends it over 50 mW.

I made an acrylic box to cover it while measuring.

-G