Coherent Model 200 LPM - Help Reading {Pic Heavy}

Hey guys,

I got a Coherent Model 200 Analog LPM and I'm trying to see 1) if it works and 2) if I'm reading it correctly or if it isn't reading my 405 and 450 correctly.

This is the meter Off and in the Battery Test position:



This next one is with the meter set to .3 It's reading the only laser I have that's been tested by another LPF member. PLE-Pro 473 that Wannaburn measured at around 100mW



I'm assuming at this point that the big numbers on top correlate to 100'S of mW

This next one is of a 5V fasttech module. Pman has measured these at around the 100-140 mark being cheap 532 modules they could be all over the place.



Again it seems to be on par with what's expected

I measured my PL520 at about 90mW which seems low for the 300mA it is set at. But maybe I just got a crappy diode... I have pictures but decided not to include them for brevity as you all get the idea.

Then there's the PL450 set at 200mA...



440mW???? :thinking: Somethings wrong here

Then there's my PHR805:



Nearly 300mW???? Again, even for a freak diode there isn't anyway these readings are correct... Right?

Any insight you guys can give would be a HUGE help. I don't have a clue as to how to actually read this, I just took my best S.W.A.G. at it.

Thanks,

Javalin

This meter is VERY strange looking. I'd be lost as to how to read it to.

I was eyeing that meter before I emailed the seller. It's not built for low power diodes. It's more accurate between 5-50W. I'd am surprised you got as good results as you did with the other lasers.

So I got a 5-50W meter!? I'd say it's still a win Buuuut, it's only got a 3W rated head so I don't think it's the same one.

Oh. May not be the same one then. It looked awfully similar and I thought the model was the same :thinking:

The meter has a >10W statement on it, but the head is max rated at 3W so the Model 200 can go higher but you have to match it with a higher power head. This one has matching serial numbers so I'm pretty confident that it's a 3W unit

Hopefully your right jav. That would be a shame to have such a high rated meter with no lasers of that extreme power lol. Would say to Rick Trent a buzz lol. Sounds like a meter he would want for that 40w monstrosity

Tmack said:

Hopefully your right jav. That would be a shame to have such a high rated meter with no lasers of that extreme power lol. Would say to Rick Trent a buzz lol. Sounds like a meter he would want for that 40w monstrosity

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Like I said, it has matching serial numbers so it is the 3W version. Why I didn't think to take pictures of the matching numbers I'm not sure... So sorry but no 40W Rick Trent measurements for me

Well it would certainly seem that if you are on the .3 range you would have to multiply .3 times whatever the reading is.

If you take your first reading that looks just over .3 on the 0-3 Watt scale and multiply it by .3 that would give you close to the reading you expected.

The second one would seem about right for 90mw

The third one would be about 400mw

The last one about 265mw

That's the best I can do as far as the scale it's on.
Following the scale and multiplier it would seem you have 0-900mw,
0-3W, 0-9W and 0-30W ranges on the meter. Of course as discussed, the head decides your limiting range although I'm sure that if you tested a 3.5W unit it would be fine if it was done quickly.
My Ophir is rated very high IF you have a good heat sink but I think it would be no issue to measure much higher than what everyone calls the 5W rating if the test was done properly so as to not heat it up much.

What output did you expect from the 3rd and last test (so I don't have to look it up?

The PHR-805 acording to These Charts I was expecting less than 150mW and they max out at about 200mW!

The PL450B is rated at 80mW but according to These Charts I was expecting 150mW at 200mA

That's why those readings don't seem logical, I will say though the PL450 is by far the brightest I own... Just now sure why I would be getting twice the output.

Wolfman29 said:

It's more accurate between 5-50W. I'd am surprised you got as good results as you did with the other lasers.

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Doesn't look like a typical 50W Coherent head though, the 30W head I have is bigger than that.


Does the head have a model number on it?

Does the head look like new?
Im assuming this is a simple head and doesn't have any kind of calibration like the ophir does right?
Does your meter look like his Arg?
Can't wait for your multimeter to come so we can see what it shows in comparison.

I just took some pictures of the head and the back of the meter. The head says model 200/3 the back also says model:3W

I would say the head is "like new" only because it has a little ripple around the out side. Not like it has been dropped or smashed, but its there. It looks like it's in excellent shape but it is older.

The back of the head looks like it has a calibration screw but it's under the "CALIBRATED 1MV/W" sticker Not sure if it's a screw for disassembly or calibration though.

Pman said:

Does the head look like new?
Im assuming this is a simple head and doesn't have any kind of calibration like the ophir does right?
Does your meter look like his Arg?

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Not sure about this meter, but mine has the calibration in the head, similar to the Ophir 20C-A heads.
I've got a FieldMax-TO, digital

DON'T mess with the calibration unless we find out that you possibly need too.
Great pics by the way. The head sensor looks brand new to me
Have you tried to get a hold of the manufacturer yet? Looks like they only list their newer stuff.
There are plenty of super cheap meters out there <$10 that can measure amps/milliamps if you can't wai for your meter to buy. Anywhere from Harbor Freight to auto parts stores to Walmart. You can always stick the cheap meter in your car or something.
Harbor Freight puts coupons in the back of car magazines and there's always a freebee offer such as a set of screw drivers or flashlight or meter along with a coupon of 20-25% off. Will warn that they have no protection so if you set it up wrong or turn the dial through a setting you shouldn't when the meter is hoked up it could blow apart. The most important feature a good well built meter gives you is fused safety.
I just did a test on a small flashlight with my Fluke 87V and the draw was 187ma. Used a free Harbor Freight CEN-TECH item # 69096 and it was not as stable a reading BUT it read from 185-187ma constantly shifting.

I can add that when your range selector is on something with a three (3) in it, you use the lower scale, the 0-3 scale.
And when your range selector has a one (1) in it, you use the upper scale, the 0-10.

Selecting from left to right, the scales read:
10W, upper scale, 0-10W
3W, lower scale, 0-3W
1W, upper scale, 0-1W
.3W, lower scale, 0-300mW

You've got a nice meter there. How much did you pay for it? Did it come with a case?

The >10W reference might refer to a neutral density filter that fits over the head, reducing the input beam by 90%, thus requiring you multiply the result by 10X.

Try digging up a manual on it to know for sure.