SOLD: Calibrated Ophir 20C Sensors

[Trevor]

Hey all!

I've got a couple spare Ophir sensors here. They're the Ophir 20C-A-1-Y.

I have calibrated these heads to read within 1% of a recently calibrated NIST-traceable LPM - so both of these heads are going to be bang on accurate.

The heads available on ebay have no such care taken - they are sold as hardware only and are not tested for calibration before they are shipped out.

They're brand new and have no marks on the sensitive surface.

Each head is $250 + shipping/fees.

Trevor

 

[Blord]

Re: FS: Calibrated Ophir 20C Sensors

I am wondering how much tweak did you do to the Ophir head. Was the factory calibration so much off ?

 

[ped]

Re: FS: Calibrated Ophir 20C Sensors

Guys if you DONT want to buy it, or dont have a valid question, can you please stop posting junk??

Nobody, least of all the OP is interested that you might have bought it if you hadnt bought something else, or that you'll wait ect ect.

It clutters up the thread with useless posts and the OP may be getting notifications, coming to the thread, wasting his time & the boards space.

Thanks.

 

[Trevor]

Re: FS: Calibrated Ophir 20C Sensors

I am wondering how much tweak did you do to the Ophir head. Was the factory calibration so much off ?

They were reading about 8% higher than they should have been. There's three multi-turn pots in the back for gain, zero offset, and response time. I used a thermally stabilized laser of known power to dial in the right gain setting - I left the other two alone.

There can be a surprising amount of calibration variation in these surplus Ophir heads.

Trevor

 

[justinjja]

Re: FS: Calibrated Ophir 20C Sensors

Not bad considering the ebay ones were up too ~270 last i checked.
Seems a little strange that they were both 8% off?
How were you measuring the voltage? (If you say a walmart multimeter, I might just have to -rep you :crackup

 

[Trevor]

Re: FS: Calibrated Ophir 20C Sensors

Not bad considering the ebay ones were up too ~270 last i checked.
Seems a little strange that they were both 8% off?
How were you measuring the voltage? (If you say a walmart multimeter, I might just have to -rep you :crackup

16-bit ADC on a high quality voltage reference.

There's definitely a lot of variability in these sensors. If you have 5 or 6 of them, there will often be at least a 5% difference between the one reading highest and the one reading the lowest. mark-in-dallas had one reading fairly significantly high right out of the box

There's got to be a reason they're getting dumped on ebay... I suspect calibration is probably a factor.

Trevor

 

[justinjja]

Re: FS: Calibrated Ophir 20C Sensors

16-bit ADC on a high quality voltage reference.

:gj: .

 

[Trevor]

Re: FS: Calibrated Ophir 20C Sensors

One head sold.

Trevor

 

[Trevor]

Re: FS: Calibrated Ophir 20C Sensors

:bumpit:

One head still available!

Trevor

 

[Pman]

Re: FS: Calibrated Ophir 20C Sensors

So are you finding the need to re-calibrate every so often or does it hold for years once it's been done? Thanks Trevor and I would expect the other to be gone quickly as well. Really appreciate how nice these heads are. Couldn't stand going back to something with a slow response time.

 

[offroadfreak8582]

Re: FS: Calibrated Ophir 20C Sensors

Once you get the ophir 20C in black, you will never go back! Lol

Free bump for this very good deal!