Author Topic: New Keithley DMM6500 and now DAQ6510  (Read 93868 times)

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Online HendriXML

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #800 on: November 22, 2019, 01:55:28 pm »
Not to interrupt this thread, but I think it's only fair to mention that the new DMM I received today from CN Rood was calibrated a lot more recent (September 2019). The fan and hum are about the same loudness.
« Last Edit: November 22, 2019, 10:45:45 pm by HendriXML »
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #801 on: November 22, 2019, 11:19:51 pm »
Maybe you can shine some light on the limitations of MULTI-MEASURE of voltage and current (excluding the 100V range bug)
In this thread we checked other DMMs (not Keithley) and also much more expensive DMMs and they all have this xx mV reading when running 1A through the device.
So that seems to be a common thing to happen, that is how it should work.
But how does Keithley or any other manufacture then say voltage can be measured while current is running through the device?  Seems to me the best you can say is it can be done but then the voltage is completely out of spec.

Anyway it's better to have it and understand what the limitations are than having it disabled.
From what I experience it's rarely a good idea to do both on one device hence why I don't really worry about the 100V range bug.

I just want to clarify since we didn't really compile a list of DMMs that perform dual V/I measurements and test them.  The DMM7510 doesn't suffer from this same hardware problem, it does dual measurements fine and provides the expected results on the voltage reading.  While both the DMM6500 and DAQ6510 cannot perform a reliable dual measurements on either the 100/1000V ranges.
 

Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #802 on: November 23, 2019, 01:51:58 am »
Maybe you can shine some light on the limitations of MULTI-MEASURE of voltage and current (excluding the 100V range bug)
In this thread we checked other DMMs (not Keithley) and also much more expensive DMMs and they all have this xx mV reading when running 1A through the device.
So that seems to be a common thing to happen, that is how it should work.
But how does Keithley or any other manufacture then say voltage can be measured while current is running through the device?  Seems to me the best you can say is it can be done but then the voltage is completely out of spec.

Anyway it's better to have it and understand what the limitations are than having it disabled.
From what I experience it's rarely a good idea to do both on one device hence why I don't really worry about the 100V range bug.

I just want to clarify since we didn't really compile a list of DMMs that perform dual V/I measurements and test them.  The DMM7510 doesn't suffer from this same hardware problem, it does dual measurements fine and provides the expected results on the voltage reading.  While both the DMM6500 and DAQ6510 cannot perform a reliable dual measurements on either the 100/1000V ranges.

Thanks for the clarification, like I said I am fairly sure this issue is logged. The next hardware revision will seek to improve it because we address all known defects. I can say however, that I dont know of any mechanism in place to notify you when this actually occurs. In the meantime, perhaps somebody (Brad) could work on a way for the issue to be worked around for your particular measurement situation (if there is such a way). I'm assuming you posted sufficient details on the Tek forum.

I talked with Brad about it and he mentioned he plans on re-engaging in the forum in December. Its unfortunate there isn't a more satisfying answer for you today.
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Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #803 on: November 23, 2019, 01:58:03 am »
Not to interrupt this thread, but I think it's only fair to mention that the new DMM I received today from CN Rood was calibrated a lot more recent (September 2019). The fan and hum are about the same loudness.

Thanks for the report, the fan is considered fairly quiet by most so I'll take that as the hum is also fairly quiet.

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Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #804 on: November 23, 2019, 02:07:04 am »
Has anyone encountered the relay constantly clicking problem on 6500 when measuring current of a light load (~4mA, switching reagulator) ?
Setting to 1A manually works, but setting it to 10mA or 100mA results in "Overflow".
The load may have spikes, but definitely nothing in the 100+mA range.
Measuring voltage with shunt (0,1Ohm) works fine (100mV Range).

Any ideas ? Anyone encountered that ?

Thanks,
Thomas

Switching regulator? You almost certainly do have larger current signals (spikes) reaching the 10's mA and 100mA ranges.. that with enough noise on top could easily explain the overflow when on fixed lower range. Perhaps you could try some averaging or other filtering to see if it makes a difference. When you have external shunt and use Vmeasure, the input filtering situation is different than when the internal Amps shunt is used. It might help explain part of why you don't see the same signals when using 100mV ??
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Offline Wintel

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #805 on: November 23, 2019, 11:09:06 am »
Not to interrupt this thread, but I think it's only fair to mention that the new DMM I received today from CN Rood was calibrated a lot more recent (September 2019). The fan and hum are about the same loudness.

Thanks for the clarification, like I said I am fairly sure this issue is logged. The next hardware revision will seek to improve it because we address all known defects. I can say however, that I dont know of any mechanism in place to notify you when this actually occurs. In the meantime, perhaps somebody (Brad) could work on a way for the issue to be worked around for your particular measurement situation (if there is such a way). I'm assuming you posted sufficient details on the Tek forum.

So this is a hardware issue and can't be fixed by a firmware update?
 

Offline E-Design

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #806 on: November 23, 2019, 01:34:34 pm »
Not to interrupt this thread, but I think it's only fair to mention that the new DMM I received today from CN Rood was calibrated a lot more recent (September 2019). The fan and hum are about the same loudness.

Thanks for the clarification, like I said I am fairly sure this issue is logged. The next hardware revision will seek to improve it because we address all known defects. I can say however, that I dont know of any mechanism in place to notify you when this actually occurs. In the meantime, perhaps somebody (Brad) could work on a way for the issue to be worked around for your particular measurement situation (if there is such a way). I'm assuming you posted sufficient details on the Tek forum.

So this is a hardware issue and can't be fixed by a firmware update?

I don't think it was investigated thoroughly enough to decide what could be done in FW (if anything).I know the issue can be improved by making some changes in hardware - For now and the foreseeable future, Applications ENG can work to help you with the issue in your particular setup.
« Last Edit: November 23, 2019, 01:40:14 pm by E-Design »
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Online HendriXML

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #807 on: November 23, 2019, 03:16:15 pm »
Somewhere in the future I would like to measure temperatures with the DMM6500. I understand it doesn't measure the cold junction temperature. So the exact temp difference is somewhat hard to tell. This can be overcome to use a known cold junction/junction temperature outside the device.
Ice water could be used, but any other known stable temperature could used as well. So I might resurrect a little project I did for fun:
https://www.eevblog.com/forum/projects/very-stable-temperature-control/
But then using a more accurate "temperature reference". Does anybody know of an affordable sensor which is specialized to measure a narrow temperature range, but very accurate?
(I think keeping the cold junction at a known temperature can be more precise than measuring an uncontrolled one in a larger range. And off course continuously updating the junction temp setting in the DMM6500 is not trivial/handy)
« Last Edit: November 23, 2019, 03:28:04 pm by HendriXML »
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Offline HKJ

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #808 on: November 23, 2019, 03:32:19 pm »
Somewhere in the future I would like to measure temperatures with the DMM6500. I understand it doesn't measure the cold junction temperature. So the exact temp difference is somewhat hard to tell. This can be overcome to use a known cold junction/junction temperature outside the device.

You cold also use another sensor type.
 

Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #809 on: November 23, 2019, 04:56:04 pm »
Maybe you can shine some light on the limitations of MULTI-MEASURE of voltage and current (excluding the 100V range bug)
In this thread we checked other DMMs (not Keithley) and also much more expensive DMMs and they all have this xx mV reading when running 1A through the device.
So that seems to be a common thing to happen, that is how it should work.
But how does Keithley or any other manufacture then say voltage can be measured while current is running through the device?  Seems to me the best you can say is it can be done but then the voltage is completely out of spec.

Anyway it's better to have it and understand what the limitations are than having it disabled.
From what I experience it's rarely a good idea to do both on one device hence why I don't really worry about the 100V range bug.

I just want to clarify since we didn't really compile a list of DMMs that perform dual V/I measurements and test them.  The DMM7510 doesn't suffer from this same hardware problem, it does dual measurements fine and provides the expected results on the voltage reading.  While both the DMM6500 and DAQ6510 cannot perform a reliable dual measurements on either the 100/1000V ranges.

I'm not talking about the 100/1000V bug I'm talking about this:
50 ohm between voltage terminals, I could add a voltage and then say it's wrong but I don't see the point, it's not 0.0mV now without one.

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Online HendriXML

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #810 on: November 23, 2019, 05:11:15 pm »
Somewhere in the future I would like to measure temperatures with the DMM6500. I understand it doesn't measure the cold junction temperature. So the exact temp difference is somewhat hard to tell. This can be overcome to use a known cold junction/junction temperature outside the device.

You cold also use another sensor type.
I haven't investigated other options yet. But the solution should have a good price/fun ratio  :-+
One of the advantage of a K-type sensor is that they're cheap (don't know about price vs quality) and their low thermal mass and large measurement range. But if someone knows of another affordable solution, then I'm certainly interested.
Will the need arise to do temperature measurements it's nice to have multiple options at hand.
« Last Edit: November 23, 2019, 05:15:31 pm by HendriXML »
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Offline Kleinstein

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #811 on: November 23, 2019, 06:41:50 pm »
With just standard 4 mm connectors it is hard to use thermo-couples. I know there are / were some electronic cold junction compensator from Omega that worked quite good. However it's nearly 20 years I used them I don't know if they are still available.
The DMM  may have to use a different voltage to temperature conversion. Possibly sensors for a cold junction are PT1000, just a PN diode or NTCs. The PT1000 could get away without extra calibration.  For use with a scanner I once use an AD592 (PAT current source, 1 µA / K) as with the meter used the scanner also worked for current and turned of the current if no in use.

 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #812 on: November 23, 2019, 08:47:10 pm »
Maybe you can shine some light on the limitations of MULTI-MEASURE of voltage and current (excluding the 100V range bug)
In this thread we checked other DMMs (not Keithley) and also much more expensive DMMs and they all have this xx mV reading when running 1A through the device.
So that seems to be a common thing to happen, that is how it should work.
But how does Keithley or any other manufacture then say voltage can be measured while current is running through the device?  Seems to me the best you can say is it can be done but then the voltage is completely out of spec.

Anyway it's better to have it and understand what the limitations are than having it disabled.
From what I experience it's rarely a good idea to do both on one device hence why I don't really worry about the 100V range bug.

I just want to clarify since we didn't really compile a list of DMMs that perform dual V/I measurements and test them.  The DMM7510 doesn't suffer from this same hardware problem, it does dual measurements fine and provides the expected results on the voltage reading.  While both the DMM6500 and DAQ6510 cannot perform a reliable dual measurements on either the 100/1000V ranges.

I'm not talking about the 100/1000V bug I'm talking about this:
50 ohm between voltage terminals, I could add a voltage and then say it's wrong but I don't see the point, it's not 0.0mV now without one.

Yeah, I see what your saying.  Although one apparently produces an error of 320uV, while the other produces an error of several volts.  Both are bad, but one is 10000x more severe.  Obviously both make the DMM6500 out of spec on dual measurements.
 

Offline gamalot

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #813 on: November 23, 2019, 09:01:12 pm »
DMM6500. Datasheet :

http://www.farnell.com/datasheets/2585589.pdf

Good to see ethernet standard, even if they got it backwards  :D

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Online HendriXML

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #814 on: November 23, 2019, 09:09:34 pm »
The LMT70A temp sensor seems to be a good choice to PID control to a fixed temperature. The idea would be not use the 4mm plugs at the "cold junction" of lets say 40 deg C.
https://www.ti.com/lit/ds/symlink/lmt70.pdf
Using an IC that's linear with voltage has the benefit that the sensed temperature can be easily read, so it can either be fine-tuned, or that the actual measured temp can be entered in the DMM as the cold junction temp.
Using a fixed temp instead of generating a correction voltage can be more precise as it is independent of the nonlinearities of the thermocouple curve.
B.t.w. pt1000 sensors seem affordable too.
« Last Edit: November 23, 2019, 09:15:23 pm by HendriXML »
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #815 on: November 23, 2019, 10:18:58 pm »
Somewhere in the future I would like to measure temperatures with the DMM6500. I understand it doesn't measure the cold junction temperature. So the exact temp difference is somewhat hard to tell. This can be overcome to use a known cold junction/junction temperature outside the device.

You cold also use another sensor type.
I haven't investigated other options yet. But the solution should have a good price/fun ratio  :-+
One of the advantage of a K-type sensor is that they're cheap (don't know about price vs quality) and their low thermal mass and large measurement range. But if someone knows of another affordable solution, then I'm certainly interested.
Will the need arise to do temperature measurements it's nice to have multiple options at hand.

I've been happy enough with this PT100 probe with the DMM6500.  I personally just clipped the wires and soldered on some banana plugs.  It is accurate enough that I don't feel like I need to perform a cold junction compensation for it with an ice water bath.  Unlike all the K-type probes I've used (they all required compensation).

https://www.amazon.com/gp/product/B075QC399C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
You can also find the same probe on aliexpress if you search around.
 
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Offline Mr. Scram

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #816 on: November 23, 2019, 10:22:12 pm »
Great to see Keithley active on the forums again. I much appreciate manufacturers showing an interest in their customers.
 

Online 2N3055

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #817 on: November 23, 2019, 10:29:43 pm »
Somewhere in the future I would like to measure temperatures with the DMM6500. I understand it doesn't measure the cold junction temperature. So the exact temp difference is somewhat hard to tell. This can be overcome to use a known cold junction/junction temperature outside the device.

You cold also use another sensor type.
I haven't investigated other options yet. But the solution should have a good price/fun ratio  :-+
One of the advantage of a K-type sensor is that they're cheap (don't know about price vs quality) and their low thermal mass and large measurement range. But if someone knows of another affordable solution, then I'm certainly interested.
Will the need arise to do temperature measurements it's nice to have multiple options at hand.

I've been happy enough with this PT100 probe with the DMM6500.  I personally just clipped the wires and soldered on some banana plugs.  It is accurate enough that I don't feel like I need to perform a cold junction compensation for it with an ice water bath.  Unlike all the K-type probes I've used (they all required compensation).

https://www.amazon.com/gp/product/B075QC399C/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
You can also find the same probe on aliexpress if you search around.

RTD sensors (PT100, PT1000) don't need cold junction compensations. That is needed for thermocouples. RTDs are absolute value sensors. Same with thermistors, but they have quite different resistance/temperature curve..
 

Offline HKJ

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #818 on: November 24, 2019, 08:30:02 am »
RTD sensors (PT100, PT1000) don't need cold junction compensations. That is needed for thermocouples. RTDs are absolute value sensors. Same with thermistors, but they have quite different resistance/temperature curve..

A sensor I like for moderate temperatures (Up to about 100°C) is LM35. Wire it to a 9V battery and it will work for a year on any voltmeter and you do not really need to do any conversions.
 
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Online HendriXML

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #819 on: November 24, 2019, 11:26:38 am »
With just standard 4 mm connectors it is hard to use thermo-couples.
Some thoughts on the temperature measurement subject.
I think Kleinstein addresses a problem with the thermocouple solution, every junction with different metals participates in the measurement. And if those can't be tightly controlled then accuracy will probably suffer (but how much? Especially when the non measurement junctions are kept the same between pos and neg).
So RTD's seem a better choice if they cover the range one wants to measure. But when doing "live" thermal probing, without a solid thermal connection between probe and DUT, accuracy will suffer a lot from environmental cooling of the probe.
The bottomline is that great accuracies are almost impossible to reach, without "specialized" setups.
In this prove of concept: determining-heat-dissipation-of-3d-printed-box-is-it-any-good I experimented in turning things around, instead of measuring different temperatures it measured how much power an enclosure can handle to keep a certain fixed temp. But that is a pretty time consuming way of getting information about thermal behavior.
So for doing quick and dirty measurements and doing reasonable accurate measurements a thermocouple seem to me the best candidate. However my hand MM has CJC, so its ready to use in that case. On the other hand there's no way of doing automated testing with it. (But that's would not be quick and dirty any more).
To conclude: creating a cold junction reference temp at 40 deg C, would (because of the handheld MM) mostly be a fun project, not one with huge benefits.
« Last Edit: November 24, 2019, 12:37:52 pm by HendriXML »
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Offline shodan@micron

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #820 on: November 26, 2019, 06:31:59 pm »
I work on the product analog design for Keithley.

Hi dear E-Design !

Please look this hardware bug(that bug is not a analog design problem, but looks very closer):

https://www.eevblog.com/forum/testgear/new-keithley-dmm6500/msg2607264/#msg2607264

https://www.eevblog.com/forum/testgear/new-keithley-dmm6500/msg2607786/#msg2607786
« Last Edit: November 26, 2019, 06:59:31 pm by shodan@micron »
 
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Offline shodan@micron

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #821 on: November 28, 2019, 01:13:15 am »
KickStart Instrument Control Software Version 2.2.0 - released.
Major changes in this release - SMU's bugfix and enhancements. (and also add some tek scope support)
 
« Last Edit: November 28, 2019, 01:16:32 am by shodan@micron »
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #822 on: November 28, 2019, 06:29:03 pm »
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #823 on: November 28, 2019, 06:50:08 pm »
So, I just leave the DMM6500 on all the time to read the lab temp.  With the new firmware, the temp reading is now left justified (before it was centered).  Not a huge deal, but I honestly liked it in the center.

880592-0
 

Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #824 on: November 28, 2019, 08:18:52 pm »
Nice I will try it tomorrow.
FYI it's not under Downloads but under Technical Documents & Software tab (on the same page)
Not everything that counts can be measured. Not everything that can be measured counts.
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