LPM Help

[NightExplorer96]

I just received the Radiant LPM from the guy on eBay but there seems to be a problem, which I think is me not setting it up correctly.

For some reason, the LPM(even with the dial turned all the way to make it go down) won't reach .000 and stays a few numbers above it. I've turned on the AC and that seemed to help bring the reading down, but it still isn't on .000

Is there anything else I should do?

-Alex

 

[BowtieGuy]

Alex, it's reading -.005 now, less than zero.

 

[Pi R Squared]

Don't turn on the AC, no heater, no fans, be sure windows are closed and the air is still, no heat source nearby, even a lamp, even your hand close to the sensor can be 1 or 2mW.

Alan

 

[NightExplorer96]

Ok, thank you guys I'll give it another go later today

@Bowtie just realized that haha.

-Alex

 

[NightExplorer96]

Ok, I gave it another go this time in a loft with no fans, no lamps, no windows open and the reading still shows -.005/-.006

Anything else I could try? Does the room need to be at a certain temp possibly?

-Alex

 

[chipdouglas]

I don't have experience with your meter. if you're trying to read a laser that is
in the hundreds of milliwatts, who cares if your off by so few mW.

just food for thought

Michael.

 

[APEX1]

honestly dude its not that far off! those tec sensors pick up he tiniest of things

 

[VisibleGreen]

The potentiometer on those are bad. You gotta replace it. (That's the little rotating thingy on the top)

 

[Cyparagon]

What does it read with the pot fully clockwise? What does it read with the pot fully counterclockwise?

 

[NightExplorer96]

@Cyparagon

With it fully clockwise it reads -.003(at its highest). With it counterclockwise it reads -.011(at its lowest)

-Alex

 

[NightExplorer96]

honestly dude its not that far off! those tec sensors pick up he tiniest of things

Haha, seems like it

-Alex

 

[Cyparagon]

You have 3 choices: Live with it, learn how to solder in a resistor, or send it to someone else that can solder in a resistor.

 

[NightExplorer96]

I'll just deal with it, I'll add the power this LPM shows on lasers & add whatever the number below 0 was.

Thanks for the help!

-Alex

 

[ARG]

The Alpha's didn't have a differential (+/-) supply voltage, so in some conditions they don't settle down to 0. Only thing to do with it is solder in some components to fix it, or subtract the zero'd reading from the measurement.

 

[NightExplorer96]

The Alpha's didn't have a differential (+/-) supply voltage, so in some conditions they don't settle down to 0. Only thing to do with it is solder in some components to fix it, or subtract the zero'd reading from the measurement.

Thanks for chipping in ARG, I'll just subtract/add the measurements when I measure lasers! Not too bad of an LPM for $42.99 :yh:

-Alex

 

[Lifetime17]

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 )