Extech automated data collection

[salvarsan]

A 40% price break at 10 $260 units is $156.
Coordinating a group buy is not easy.

On reliable code for automating the 380193 data collection, I get sort of okay prototype code.

[root@Adelie lcrmeter]# python RLtest03.py
Serial port 0 found. Init: 1200,7,E,1

Resistance test mode @ 120 Hz
Rac @120Hz: 9.287 K
Rac @120Hz: 9.289 K
Rac @120Hz: 9.287 K

Resistance test mode @ 1000 Hz
Rac @1000Hz: 15.609 K
Rac @1000Hz: 15.606 K
Rac @1000Hz: 15.609 K

Inductance test mode @ 120 Hz
L @120Hz: 8.928 H Q @120Hz: 0.7422
L @120Hz: 8.928 H Q @120Hz: 0.7422
L @120Hz: 8.929 H Q @120Hz: 0.7422

Inductance test mode @ 1000 Hz
L @1000Hz: 8.540 H Q @1000Hz: 3.343
L @1000Hz: 8.539 H Q @1000Hz: 3.339
L @1000Hz: 8.539 H Q @1000Hz: 3.339

[David King]

I emailed my local distributor about matching the 234 price and they responded asking for a link to that price. And yes a group buy will be like pulling teeth around here.

[salvarsan]

I emailed my local distributor about matching the 234 price and they responded asking for a link to that price. And yes a group buy will be like pulling teeth around here.

Passive Component LCR Meter [LCR200] - $233.99 : Azhtech, Your Qualified Resource for Test Equipment

Test Equipment Depot (Melrose, MA) also sells on eBay:
http://www.ebay.com/itm/Extech-LCR20...#ht_1233wt_907

You can contact TestEquipmentDepot directly and request their eBay price.

[enkindler]

Just a quick note BK the Precision 879B LCR meter also does impedance,Theta, and ESR, Uses USB for connectivity and uses SCPI commands (mostly human readable) and is in the same price range as the LCR200.

Not that the LCR200 is a bad unit but if you want data logging and remote control it may be an option for you.

[salvarsan]

DON'T DO IT!!!!!

The 380193 is spec'd for a D factor <= 0.5 which allows it to give a halfway accurate inductance reading on pickups.
It just works, warts and all.

The LCR200 is spec'd at D <= 0.1, and will very likely give crap readings for our intended purposes.
In light of this, the LCR200 may be a case of "more features, less function".

B&K lost a lot of LCR meter market share to Extech until they made a meter that would handle the higher resistance of pickup-like coils.

[David King]

Salvarsan,

I got the message loud and clear. Thanks for the head's up and taking one for the team as usual.

[Joe Gwinn]

I have never been happy with anything I ever bought from B+K. So I no longer buy their stuff. There are better choices.

[the great waldo]

Hi Joe

What would you recommend

Cheers
Andrew

[Joe Gwinn]

Hi Joe

What would you recommend

For a handheld LCR meter, the Extech 380193 if you need it now, because we know that the 380193 is suitable for our purpose.

One assumes that there are other suitable kinds of LCR meters being made, but we will need to identify and verify them. For this, the group can help by identifying makes and models that claim to measure the inductance of lossy coils (D exceeds 0.5 (equivalently, Q less than 2), at 1 KHz) so we can assess them and compare them.

The Extech 380193 was originally validated by comparison with a Maxwell-Wien Impedance Bridge in 2004. Such bridges were the mainstay of the national standards labs for about a century, until digital came along.


For other kinds of instruments, it varies.

[salvarsan]

The Extech 380193 was originally validated by comparison with a Maxwell-Wien Impedance Bridge in 2004. Such bridges were the mainstay of the national standards labs for about a century, until digital came along.

Joe is too modest.

It was he who verified the Extech 380193's suitability for intended use.

[enkindler]

For a handheld LCR meter, the Extech 380193 if you need it now, because we know that the 380193 is suitable for our purpose.

One assumes that there are other suitable kinds of LCR meters being made, but we will need to identify and verify them. For this, the group can help by identifying makes and models that claim to measure the inductance of lossy coils (D exceeds 0.5 (equivalently, Q less than 2), at 1 KHz) so we can assess them and compare them.

The Extech 380193 was originally validated by comparison with a Maxwell-Wien Impedance Bridge in 2004. Such bridges were the mainstay of the national standards labs for about a century, until digital came along.


For other kinds of instruments, it varies.

Thank you for all of your hard work.

I don't see Extech 380193 claiming anything under a DF <0.5 Is it possible they had a hardware revision due to component availability and changed the device? Or maybe they are just looking to match the other makers accuracy?

The capacitance accuracy of the 380193 at @1K only states a DF <0.5 at 199.99μF everything else is stated at <.1

I always figured in a fixed frequency LCR reading of a pickup that it was a relative measurement anyway but my main source of income is at a medical electronics manufacture and our products are heavy in analog circuits so if you give me what you want bounds to test between I will validate any newer device I can borrow from friends.

I only have a few slightly over 100 sets of pickups in customers hands and they have mostly been p90/humbucker style so this is going to be a guess but I think at 1 kilohertz ~.45 is as high as I have seen on DF all were less than 4H at the same frequency. This was on an auction sourced HP 4262A with questionable calibration.

Is this a safe range of what you are looking for?

The HAMs seem to be doing DIY or small run VNA's like these days. I am surprised someone hasn't built one for plotting out pickups and tone stacks.

[Steve Conner]

The HAMs seem to be doing DIY or small run VNA's like these days. I am surprised someone hasn't built one for plotting out pickups and tone stacks.

It's very easy to build an audio network analyser using a bridge circuit driven by your PC soundcard. The ones I'm familiar with drive the circuit with pseudo-random noise and perform a FFT of the output with averaging, but swept sine is used too.

You could get a "dynamic signal analyzer" from HP many years ago that worked like this. The speaker measuring device from Dayton is the same, it is basically a USB soundcard with a built-in bridge. I've been using the technique, minus the bridge, to test filters and tone controls for years.

The hard part is getting software to do it that's easy to set up, understandable and free. I use Spectrum Lab which is intended for ham radio applications, but can be configured to do almost anything. Better options are available, but they cost money.

[salvarsan]

Some of us have Syscomp's CGR-101 USB scope.

It does network analysis, so I think a good add-on for it would extract data
from the Bode plot below resonance and calculate Inductance, perhaps
distributed capacitance at resonance, and whatever else we could think of.

While I used to think the software's having been written in Tcl/Tk was a
questionable choice, Tcl scripts execute very fast and are trivially
portable across different workstation platforms.

[Joe Gwinn]

I don't see Extech 380193 claiming anything under a DF <0.5 Is it possible they had a hardware revision due to component availability and changed the device? Or maybe they are just looking to match the other makers accuracy?

The capacitance accuracy of the 380193 at @1K only states a DF <0.5 at 199.99μF everything else is stated at <0.1

The manual that came with my Extech quotes D<0.5 for inductance. The manual is marked "380193 V1.6 10/03" on every page.

The most recent manual, marked "380193-EU-EN-V2.3-5/11", says the same thing. The D limit is in the first line of the relevant table.

I always figured in a fixed frequency LCR reading of a pickup that it was a relative measurement anyway but my main source of income is at a medical electronics manufacture and our products are heavy in analog circuits so if you give me what you want bounds to test between I will validate any newer device I can borrow from friends.

The basic test is a 2-henry iron-core (laminated) inductor in series with a 10K resistor. One can measure the components individually, and see how close the instrument under test gets to the correct answer when presented with resistor and inductor in series.

I only have a few slightly over 100 sets of pickups in customers hands and they have mostly been p90/humbucker style so this is going to be a guess but I think at 1 kilohertz ~0.45 is as high as I have seen on DF all were less than 4H at the same frequency. This was on an auction sourced HP 4262A with questionable calibration.

Is this a safe range of what you are looking for?

The smaller the inductor and the larger the resistor, the more severe the test. My rough and ready test is a 2 H iron-core inductor in series with a 50 Kohm pot - how large a series resistance will the LCR meter tolerate without gross error?

The HAMs seem to be doing DIY or small run VNA's like these days. I am surprised someone hasn't built one for plotting out pickups and tone stacks.

We have discussed such things too, but this approach is a bit complex for most pickup makers to find useful. It's really a research tool.

[enkindler]

The manual that came with my Extech quotes D<0.5 for inductance. The manual is marked "380193 V1.6 10/03" on every page.

The most recent manual, marked "380193-EU-EN-V2.3-5/11", says the same thing. The D limit is in the first line of the relevant table.



The basic test is a 2-henry iron-core (laminated) inductor in series with a 10K resistor. One can measure the components individually, and see how close the instrument under test gets to the correct answer when presented with resistor and inductor in series.



The smaller the inductor and the larger the resistor, the more severe the test. My rough and ready test is a 2 H iron-core inductor in series with a 50 Kohm pot - how large a series resistance will the LCR meter tolerate without gross error?



We have discussed such things too, but this approach is a bit complex for most pickup makers to find useful. It's really a research tool.

OK I think we are just having a NASA style units conversion issue.

"(D exceeds 0.5 (equivalently, Q less than 2), at 1 KHz) "

D=.5 == Q=2 I thought you were saying we need Q to approch 1/2 or D needed to be larger than .5 e.g. D=.75 which is the same as Q = 1 1/3

The new BK unit claims to support D<.5 I have a friend who has one and I may have access to the new agelent units although they are at a much higher price point than the Extech units.

I poked around at work at all our work is ultrasonic so I don't see any of these small units.

Thanks again for sharing this information.