Author Topic: New Keithley DMM6500 and now DAQ6510  (Read 296866 times)

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Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1100 on: October 20, 2020, 11:48:42 am »
Just found out Kickstart now costs ~$1500AUD ex GST. This is a deal breaker for me. How much did this cost previously?

https://www.tek.com/keithley-kickstart

Website shows $593 to $999 USD. Which is close to what you found.. not sure what the differences are in the range.

ISTR that it used to cost ~ $250 USD

The special deal for it included free with a DMM6500/DAQ6510 has expired and is no longer offered.

eplpwr,
The virtual machine idea sounds like a good workaround. Did you contact somebody about your license that disappeared after redeeming?  Its likely a matter of bugs in the website/system and not malice or greed.   :-//
« Last Edit: October 20, 2020, 11:54:14 am by E-Design »
The greatest obstacle to discovery is not ignorance - it is the illusion of knowledge.
 

Offline eplpwr

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1101 on: October 20, 2020, 01:38:29 pm »
eplpwr,
The virtual machine idea sounds like a good workaround. Did you contact somebody about your license that disappeared after redeeming?  Its likely a matter of bugs in the website/system and not malice or greed.   :-//

I opened a case with Tek support 29th of July.  The case was even escalated to a Tek Manager, Alexander Ulyanov, who I heard from last time the 3rd of August. The case is obviously stone cold. The attention I got initially was based on the (wrong) assumtion that I was using a website for paying Tek S/W customers.

When it became clear that I was trying to redeem promo licenses that I had gotten "for free" upon registration of two pieces of newly bought meters (DAQ6510 and DMM7510 respectively), and three pieces of used SMU:s from eBay, the interest in helping me redeem the licenses dropped to zero. Tactically, I should have redeemed the licenses related to the SMU:s initially, then I could have referred to the equipment I bought new ... but unfortunately I did it the other way around. Anyway, I think the code to send out promo licenses is disabled since the promo ended - too bad they left the redeem button in place.

One thing Keysight got right with BenchVue is that the equipment is the license - when a qualified piece of equipment is found the related software is activated. That's a solution Keithley should copy.
« Last Edit: October 20, 2020, 01:44:42 pm by eplpwr »
 
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Offline KaneTW

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1102 on: October 22, 2020, 04:48:44 pm »
My DMM6500 arrived today. Pretty nice instrument. Shame the Kickstart offer expired, but alas.
 
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Offline uski

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1103 on: October 22, 2020, 05:56:20 pm »
I ordered a DMM6500 a few days ago. Anything I need to know ?
I already know that I need to make sure it has the latest firmware, due to the battery drain issue.
I also know the Kickstart offer expired but honestly I don't really care, plus I got a good price on the meter
 

Offline KaneTW

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1104 on: October 23, 2020, 01:55:48 am »
Haven't used it enough yet. Btw, 5 minutes with dnSpy can make your trial eternal and remove the nag dialog :)
« Last Edit: October 23, 2020, 01:57:21 am by KaneTW »
 
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Offline Mr. Scram

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1105 on: October 23, 2020, 07:36:23 pm »
I ordered a DMM6500 a few days ago. Anything I need to know ?
I already know that I need to make sure it has the latest firmware, due to the battery drain issue.
I also know the Kickstart offer expired but honestly I don't really care, plus I got a good price on the meter
It's quite easy to get started without reading a manual, especially compared to many other meters. As with any tool of this grade, there are things worth reading the manual for. I can't remember anything major, but a few things which will improve your understanding of what you see like what auto impedance mode means exactly.
 
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Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1106 on: October 26, 2020, 10:18:28 am »
Don't forget to have fun with your new Keithley but maybe not too much ;)

Not everything that counts can be measured. Not everything that can be measured counts.
[W. Bruce Cameron]
 
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Offline JimKnopf

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1107 on: November 04, 2020, 08:19:50 pm »
Is it possible to set or view the testfrequency on DMM6500 when measuring Capacitors? Usually Capacitors are tested with 120Hz by manufacturer for specification purposes. I couldn't find any information about that in the datasheets.

On my Der EE DE-5000 LCR-Meter i can set different testfrequencys. Even the more cheaper  Peaktech 3705 has information about this (not unimportant) information in it's datasheet. I noticed, that the DMM6500 uses different testfrequencies and voltages for different capacitors.

As an example: With the DE-5000 i measure a 100µF electrolytic capacitor at 100Hz. It show me 93,25µF. With an Oscilloscope i measure 0,835V and 107Hz.
Measuring the same capacitor with the DMM6500, it show me 100,64µF. But the testvoltage is 0,76V and the testfrequency is 2,56Hz.
I have a some examples in a small table. Up to 10µF the capacitance readings are equal to the DE-5000. But there is a gap on higher capacitor values. I know (thanks to bob91343) that:
                                  "You can't measure capacitance.  What you can measure is the effect the capacitance has and then compute
                                    what capacitance  would have that effect."
So my question is, how can set the testfrequency or show it on the display. Is there a script for that? I'm using the latest 1.7.3 firmware.
"

 

Offline KaneTW

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1108 on: November 04, 2020, 10:56:09 pm »
The test frequency is not well defined and depends on the measured capacitance.
 

Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1109 on: November 05, 2020, 01:04:11 am »
Is it possible to set or view the testfrequency on DMM6500 when measuring Capacitors? Usually Capacitors are tested with 120Hz by manufacturer for specification purposes. I couldn't find any information about that in the datasheets.

On my Der EE DE-5000 LCR-Meter i can set different testfrequencys. Even the more cheaper  Peaktech 3705 has information about this (not unimportant) information in it's datasheet. I noticed, that the DMM6500 uses different testfrequencies and voltages for different capacitors.

As an example: With the DE-5000 i measure a 100µF electrolytic capacitor at 100Hz. It show me 93,25µF. With an Oscilloscope i measure 0,835V and 107Hz.
Measuring the same capacitor with the DMM6500, it show me 100,64µF. But the testvoltage is 0,76V and the testfrequency is 2,56Hz.
I have a some examples in a small table. Up to 10µF the capacitance readings are equal to the DE-5000. But there is a gap on higher capacitor values. I know (thanks to bob91343) that:
                                  "You can't measure capacitance.  What you can measure is the effect the capacitance has and then compute
                                    what capacitance  would have that effect."
So my question is, how can set the testfrequency or show it on the display. Is there a script for that? I'm using the latest 1.7.3 firmware.
"

The instrument uses the DC current source to charge the capacitance under test. As such, to understand the test waveform, it isn't a question about the test "frequency". Its a matter of current source range (used in Ohms) and the capacitance value. The capacitor is calculated by measuring the voltage slope of the charge and discharge curves. The current source range is chosen based on the capacitance range. Hard coded in firmware.

Put a scope on your capacitor if you want to see more details.
The greatest obstacle to discovery is not ignorance - it is the illusion of knowledge.
 

Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1110 on: November 06, 2020, 01:24:45 pm »
If you want to measure it based on/for a Sin wave (at a certain frequency) you need a function generator and use your DMM6500 to measure the AC voltage or current.
You can let the DMM6500 do the math.
« Last Edit: November 06, 2020, 01:27:09 pm by KedasProbe »
Not everything that counts can be measured. Not everything that can be measured counts.
[W. Bruce Cameron]
 

Offline JimKnopf

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1111 on: November 06, 2020, 02:37:54 pm »
If you want to measure it based on/for a Sin wave (at a certain frequency) you need a function generator and use your DMM6500 to measure the AC voltage or current.
You can let the DMM6500 do the math.

How exactly can i let the DMM6500 do the math? Do i need to write a script for that? Or are there existing solutions?

 
 

Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1112 on: November 07, 2020, 09:20:19 am »
Yes you will need to write somethings.
If you only need it for a few times you can do it in excel, if you want to put more time in it you can make a DMM6500 script.

Since you have a DE-5000 that is using a frequency and not a charge speed measurement (DC measurement) I assume you want to measure it only a few times on the DMM6500.
Not everything that counts can be measured. Not everything that can be measured counts.
[W. Bruce Cameron]
 

Online macaba

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1113 on: December 08, 2020, 06:09:34 pm »
Hi all,

Received my DMM6500 today, first impressions were good so I started to set up an experiment whereby I would use the 10MΩ input impedance as a shunt resistor in DCV mode to measure the leakage of a capacitor when 10V applied to the other side of the capacitor.

To my surprise, both the 100mV and 1V manual range setting gave me "Overload" even though the reading in the 10V range is 0V (1PLC).

Going back to basics, I disconnected everything and the overload disappeared. Then I attached the input leads with nothing connected on the ends; Overload.

Switching from Measure to Digitizer, at the slowest rate 1KSPS, I can clearly see lots of 50Hz mains on the graph.
(I'm assuming both ADCs use the same input amplifier circuitry)

In my lab, it ranges from 1Vpp-3Vpp. (various combinations of switching equipment off & lights off & using grounding wriststrap)
In my outdoor workshop, it ranges from 100mVpp-200mVpp. (lights off, then on)

So that explains the why; the input amplifiers are saturating and triggering hardware overload detection.

A couple of acquaintances of mine fired up their 34401A's, attached floating leads and placed them in worse case positions (near SMPS and power strips) and the 34401A works fine on the minimum range.

Is my DMM6500 faulty, or does it have poor isolation by design? Perhaps I need to shield everything or scale back my expectations?

 

Offline Kleinstein

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1114 on: December 08, 2020, 07:36:38 pm »
The HP34401 has quite a bit of capacitance at the inputs.  Another point may also if it uses the 10 M input impedance more.
1 m of cable give some 100 pF of capacitive coupling to the environment. So a few nF at the input can make a difference.
The DMM6500 is relatively, at least in the digitize mode and for this reason it may have considerable lower input capacitance.

One usually does not use open leads. Sensitive measurement from high impedance source should use shielded wired and maybe connect the low side input (or a separate guard terminal if present) to a kind of ground.

One can get a crude estimate of the input capacitance: use a small coupling capacitor (e.g. some 10--100 pF) to a function generator and check the amplitude ratio.

In Germany one could try reversing the mains plug to see if this make a difference. In the UK the phase pin is fixed, though for some reason it may not be the best way around (e.g. swapped in the meter or mains wiring). Also check it PE is connected - I don't know the details on the DMM6500, but it may use PE for EMI suppression caps.

To see if there is much hum coming from the meters, one could measure the 50Hz current flow from PE to the low side input of the meter. One may be able to measure it with the DMM6500 itself: AC current mode and current input (hi) to PE.
 
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Online macaba

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1115 on: December 08, 2020, 08:29:31 pm »
To see if there is much hum coming from the meters, one could measure the 50Hz current flow from PE to the low side input of the meter. One may be able to measure it with the DMM6500 itself: AC current mode and current input (hi) to PE.

As suggested, I connected a lead from the PE screw on the rear panel, to the current input, digitize mode with 100uA range. 140nApp. Attached screenshot shows this, followed by unplugging of lead halfway through the trace.

It's difficult for me to know whether this is to be expected or not? Would a Keysight 3446x meter perform better?
 

Offline Kleinstein

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1116 on: December 08, 2020, 08:47:11 pm »
The 140 nA_pp are at least within the specs ( < 600 nA_pp).

The number looks relatively good - it corresponds to something like 1 pF towards 100 V AC, if my calculation is correct. This is at least way better than just an of the shelf transformer.
 
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Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1117 on: December 09, 2020, 03:13:01 am »
Kleinstein is a keen observer.

The transformer is indeed a special design. And because of the digitizer function, the front end has higher bandwidth and does respond more quickly to brief overloads. Meters with lower input bandwidth / more input filtering generally filter the signal enough to avoid the brief overload (as shown with the Keysight instrument).

These behaviors macaba has seen are normal and expected for this instrument.
The greatest obstacle to discovery is not ignorance - it is the illusion of knowledge.
 
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Online macaba

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1118 on: December 09, 2020, 07:36:33 am »
My thanks to Kleinstein and E-Design, we’ve covered the why and the how. It’s now a good reason for me to throw together a JFET OA TIA.

I see the max. spec for linearity on the datasheet, is there any public data on typical linearity?
 

Offline Kleinstein

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1119 on: December 09, 2020, 09:45:19 am »
Linearity measurement at the 1 ppm and below level is a tricky thing.  The INL measurement gets extra difficult (and slow) with a meter with a relatively noisy reference like the LM399, as the INL tests would usually use an external precision source (e.g. high end calibrator).

There is a thread on DMM linearity testing, but AFAIR this are mainly more higher end examples that are shown.

The INL error can vary between different units. Some INL contributions depend on resistor matching or TC matching and this can vary quite a bit from near perfect to poor with bad luck.

The INL specs are to be taken with a grain of salt, especially if they are good. I would not take them to serious. It is more like a reasonable estimate with quite some uncertainties.  There are examples where the official INL specs are overly optimistic.

Because of the time needed, I would not expect very much production testing of the INL, especially not with a more low cost type like the DMM6500. There should be a basic test, likely the classic turn over test and maybe the test if 2 x about half the voltage sums up correctly. This would catch most cases of things like a poor resistor array. The turn over part is usually even part of the calibration procedures, though maybe not with enough repeats to get a reliable INL point.
 

Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1120 on: December 09, 2020, 12:52:36 pm »
The linearity and noise are mostly guaranteed by design and do vary from unit to unit. Error budgets and statistical analysis have provided comfortable margins in guaranteeing these specs for production.
Kleinstein is correct again - this instrument is positioned for a lower cost and thus cannot do many of the production tests other higher end meters might be doing.

While there are no specific production tests evaluating full linearity, I could check into finding some typical test data if its useful to you? I don't think any of it is public, but I don't think that kind of data is confidential either.
Keithley in general, is pretty open to reasonably sharing technical data with customers.
« Last Edit: December 09, 2020, 12:57:26 pm by E-Design »
The greatest obstacle to discovery is not ignorance - it is the illusion of knowledge.
 
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Online analogRF

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1121 on: December 09, 2020, 01:41:05 pm »
Haven't used it enough yet. Btw, 5 minutes with dnSpy can make your trial eternal and remove the nag dialog :)

I am getting my 6500 in a few hours  :) :-DMM
I have been reading all the reviews and parts of this thread. Can you please point me to what "dnSpy" is and what it does?

 

Online macaba

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1122 on: December 09, 2020, 02:57:30 pm »
I could check into finding some typical test data if its useful to you?

Yes please, it's useful to me by virtue of educational value, and it's probably useful for others to add to DMM comparison charts. I may do my own INL testing (mostly for the educational value to learn procedure, etc) so the data will give me a broad benchmark for what the output from my testing should look like.

 

Offline Kleinstein

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1123 on: December 09, 2020, 04:44:57 pm »
A basic INL test is a good exercise to learn about precision measurements. It's mainly one type of test one can do:  Have two external (isolated from the DMM, but possibly linked to each other) reference voltages and check if they sum up correctly.  So the measurement of the two sources separate is compared to both sources in series. The turn over test can be seen as a special case where the same source is used with both polarities.

The two source can be directly linked, like one reference and a divider and simple buffer. Getting a stable (needs to be short time only) source is already some effort, but still doable - for this thread it gets a bit far off topic.
It usually need several measurement cycle and it could be better to use some switches instead of swapping cables by hand (this can cause thermal EMF trouble for some time, so it's slow). Comparing the cycles gives a good idea on how good the readings are.

The < 1 ppm  INL spec. for the DMM6500 is quite good. So it gets tricky to check this - it needs quite some care with thermal EMF, possible EMI  and drift / popcorn noise of the reference.
 
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Online analogRF

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #1124 on: December 09, 2020, 07:58:42 pm »
I just joined the club a few hours ago  :-DMM :-DMM  ;D ;D
I connected this 4 wire short circuit to the device and let it warm up for an hour or so

here are the ohm and mV DC

is there anything I should be concerned about?

I cannot say I am disappointed but perhaps I was expecting a little better than this

Firmware 1.0.0.4b

EDIT: I used rate of 2 and Filter ON
also the resistance value never quite settles, the last two digits (only) keeps moving around that average
« Last Edit: December 09, 2020, 08:21:08 pm by analogRF »
 


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