Power Meter Calibration and Comparison

IgorT said:

Kenom: Did you check the PSU output voltage, when fixing the laser?

Dave: Could you measure the PSU output voltage?

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Psuedo had forgotten to pack the psu when he shipped it back to me for repairs. So I didn't use the psu for setting the power on the laser. I used my bench psu set to 9v. If this is the problem it will be remedied when it comes back to me and I verify the lasers power with the psu.

I know beyond a shadow of a doubt that the sensor on the knimrod build is NOT the PM10-19C. When I contacted coherent for specs on the heads they indicated to me they didn't even have them in the system and had no clue what they were. I'm sure this was the default responce to any query about any of thier products not sold specifically from them. Thier resold products are just not supported by them. The PM10-19C looks completely different. Not just the screw holes but also the mounting plate and the location of the connector on the head. These boards came with two different heads: one with 8 screws and one with 12 screws.

Are you suggesting they are counterfeit or it's just another one from Coherent?

Remember, the brass plate at the back is added later and not part of the head.

Zom-B said:

Are you suggesting they are counterfeit or it's just another one from Coherent?

Remember, the brass plate at the back is added later and not part of the head.

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Nah it's not the back plate I'm talkin bout. I've no doubt that they are coherent sensors. The PM10-19C is a fairly new sensor. These have been sitting in a warehouse for a long time. They are old. Since coherent, unlike scientech, doesn't keep specs and such for older equipment it's really impossible (unless you pay to have it calibrated or fixed) to find out from coherent what these sensors are. Maybe we should do a slush fund like we did for this to send one back to be fixed. I do have one that had a broken thermopile and needs to be fixed. Then we will all know what these sensors are and the capabilities.

IgorT said:

[quote author=pullbangdead link=1217029972/480#492 date=1223601011]

Seeing, how the red measures "the same" on both, but the blu not, it's not the metr's amplifiers, that are calibrated incorrectly.. It's the coatings.... If the coatings actually were spectrally flat down to 400nm, the difference would be the same with both lasers..

I feared this would happen. But it is strange, that it happens on thermopiles with coatings specifically made for a certain wavelength range.

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I have the same setup as Dave but with 3 different head, 2 of which came calibrated with the meter and the 3rd was purchase after.  All 3 heads have different coating and 1 look like it was spray on while the other 2 are a sheet of metal.  When I measure my 405nm with the 3 heads I only see 1-3% differences between them.  So I don't think the coating is a big deal from what I have seen with my setup.  
This is my setup;

Scientech
365 meter
36-0001 head
38-1UV5 head
38-2UV5 head

I can compair my reading with Dave when the lasers come to me.  I know Dave has a Scientech 365 and a 36-0001 head and I can match that setup to see what the reading are.  

That's interesting about the different coatings not making much of a difference, good info to know.

On the couple of PM OEM Sensors I bought recently, they are marked as PM10-19B; these are not the ones from back when they sold for $30.00 or so I believe it was.

Coherent made a BNC to 25 pin adapter for me that contains an eprom in the shell of the 25 pin amp connector and within that eprom I'm told is where my calibration info is stored, in-fact it has a seal tamper seal on the connector that I can't remove without voiding the warranty on the adapter and it's calibration.

and now I've got a sensor to go with that $2000 meter.  $795 is what this sensor retails for and I got it for a little over $130

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=260294799674&ssPageName=STRK:MEWA:IT&ih=016

I love the exhileration of bidding on something and hoping beyond hope that your bid is going to end up being the highest one and that your going to get one hell of a deal on something you know is worth 4x what they have it listed for. It's the new sex and I can understand why folks like Gooeygus end up spending so much money there.
;D

Congrats! that looks like a really nice Sensor that should bring you many years of good measurements.  

Kenom said:

and now I've got a sensor to go with that $2000 meter.  $795 is what this sensor retails for and I got it for a little over $130

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=260294799674&ssPageName=STRK:MEWA:IT&ih=016

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"You were outbid by Kenom"

We really should coordinate better.  One of us could have had it for $75

Can I borrow it from time to time?   [smiley=engel017.gif]

Peace,
dave

YOu bet. You got a meter to go with that sensor? I'd be more than happy to ship the whole thing for ya to play with.

Kenom said:

YOu bet.  You got a meter to go with that sensor?  I'd be more than happy to ship the whole thing for ya to play with.

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Scientech Vector S310

Waiting on another deal on an Astral Series calorimeter.

I am unwilling to spend $700 for a calorimeter when I have the 365/360001 still working

Congratulations

If you see another one, keep me in mind

Peace,
dave

Who did Kenom bid against on here?

electron said:

Who did Kenom bid against on here?

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That would be me. I didn't tell him I was bidding. I actually thought that he had a calorimeter for his new LPM. I was wrong. With the "anonymous" ID's in eBay now, if we don't tell each other what we are bidding on, then we end up jacking up the price against each other.

Oh well. If I had to lose to someone, I'm glad it was Kenom

Peace,
dave

Kenom said:

It's the new sex and I can understand why folks like Gooeygus end up spending so much money there.
;D

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I dont know what on earth you're talking about :-X :-X :-X



The trick to ebay is contacting the other people who you think may want to bid on the item, so you can get it cheap! ;D

daguin said:

[quote author=Kenom link=1217029972/520#520 date=1223770848]YOu bet.  You got a meter to go with that sensor?  I'd be more than happy to ship the whole thing for ya to play with.

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Scientech Vector S310

Waiting on another deal on an Astral Series calorimeter.

I am unwilling to spend $700 for a calorimeter when I have the 365/360001 still working

Congratulations

If you see another one, keep me in mind

Peace,
dave[/quote]

If I find another you can bet I'll be letting you know. That meter is actually better than the one I've got. Did you pay full retail for it? This is the first I've heard of this meter.

GooeyGus said:

[quote author=Kenom link=1217029972/500#517 date=1223764486]It's the new sex and I can understand why folks like Gooeygus end up spending so much money there.
;D

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I dont know what on earth you're talking about :-X :-X :-X



The trick to ebay is contacting the other people who you think may want to bid on the item, so you can get it cheap! ;D[/quote]

I actually thought I was bidding against someone else I knew who was looking for one of these sensors and was totally freaking out that I was going to be outbid. he wouldn't have cared less if he was bidding against me and would have been a bit more agressive in bidding. So, I kept it to myself and didn't let anyone know for fear of not even getting a chance at the sensor, and not tipping him off to the auction if he didn't know.

I'm sure had I know it was daguin I would have made arrangements to either bow out or something if he bow'd out. One way or another everyone would have been happy. (I hope).

I do hope there's no ill will over the auction.

Kenom said:

If I find another you can bet I'll be letting you know.  That meter is actually better than the one I've got.  Did you pay full retail for it?  This is the first I've heard of this meter.

 I'm sure had I know it was daguin I would have made arrangements to either bow out or something if he bow'd out.  One way or another everyone would have been happy. (I hope).

I do hope there's no ill will over the auction.

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Two sets of eyes are better than one set  I did NOT pay full retail.  I rarely do.

For some reason I thought you already had a calorimeter for your new LPM, so I didn't even consider coordinating with you.

I am happy.  This is no problem, Ken.  As I said before, I am very pleased it was you.

Peace,
dave

[highlight]**EDIT**  [/highlight]Back on topic -- Scopeguy20 came over this evening with his lovely wife.  He has the test lasers now

I just cleaned my coherent sensor. After looking through my violet goggles I noticed fluorescing specles on the coating.

I took a violet laser focused at a ~1" spot and, while wearing goggles, aimed it at the coating. I used a q-tips and sure enough the speckles moved around. This can only be if the speckles are alien to the sensor, like dead skin cells. I continued by rubbing the coating with the q-tips with very short strokes. (still wearing goggles and shining 1" violet) First in a corner to prevent large-scale damage. It didn't damage. I continued cleaning the entire area and while doing so, I blew on the coating to blow away any airborne dust before it settles again (this helped a lot). Afterwards there were only two or so speckles that wouldn't move, the rest is black now, as seen through my glasses when sining violet.

Curiously though, before I started cleaning, the center 5mm already looked darker than the surrounding. Maybe dust on that spot got charcoaled by lots of powerful lasers I aimed at that spot (up to 300mW lately).

After cleaning, the sensor didn't seem any more sensitive for 660nm but my 405nm suddenly read 10mW higher (though I can't rule out the possibility of temperature influences, as room temperature is 3°C warmer than usual) Temperature is still the same, I read the wrong sensor from my diy weather station