Author Topic: New Keithley DMM6500 and now DAQ6510  (Read 296875 times)

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Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #575 on: July 27, 2019, 02:03:22 pm »
Does it make noise in standby?
Not fan noise because they are off but you can hear the mains hum.  (hence my question)
« Last Edit: July 27, 2019, 02:41:20 pm by KedasProbe »
Not everything that counts can be measured. Not everything that can be measured counts.
[W. Bruce Cameron]
 

Offline Hugoneus

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #576 on: July 29, 2019, 01:51:15 am »
Some more information for you guys! :)

You can watch the video here: [48 Minutes]

youtu.be/Lezd27BzQLo
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #577 on: July 29, 2019, 04:23:30 am »
This video really makes me wish I waited and picked up a DAQ6510 vs the DMM6500.  I do foresee the DMM6500 going up on eBay eventually since 9 out of 10 times I use my other meter, while the DMM6500 mostly just logs temperature continuously.  No real complaints though, it does a great job logging those temps :)
« Last Edit: July 30, 2019, 01:35:28 pm by JxR »
 

Offline hwj-d

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #578 on: July 29, 2019, 09:21:35 am »
But the very most of them you can do with dmm6500 and scancard too?  :popcorn:
 

Offline KedasProbe

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #579 on: July 29, 2019, 09:44:51 am »
Some more information for you guys! :)

You can watch the video here: [48 Minutes]

youtu.be/Lezd27BzQLo
What took you that long ;) nice to get some extra example of configuring a trigger and yes FFT please :)
Tip: if you just want to demo a new script you can just record the webinterface (no camera setup etc, saves time)
I may make one later this week.

I couldn't justify the extra price for the DAQ6510 + Cards though, most of it is present in the DMM6500 and I would probably not use the cards very often assuming I would buy one.
edit: Also the DMM6500 has a 10A input at the back while the DAQ6510 is limited to 3A with a high burden voltage.
« Last Edit: July 29, 2019, 10:59:51 am by KedasProbe »
Not everything that counts can be measured. Not everything that can be measured counts.
[W. Bruce Cameron]
 

Offline Mr. Scram

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #580 on: July 29, 2019, 10:03:53 am »
But the very most of them you can do with dmm6500 and scancard too?  :popcorn:
A K2000 or DMM6500 with scan card is effectively a DAQ, unless I'm missing something.
 

Offline drummerdimitri

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #581 on: July 29, 2019, 11:24:47 am »
But the very most of them you can do with dmm6500 and scancard too?  :popcorn:
A K2000 or DMM6500 with scan card is effectively a DAQ, unless I'm missing something.

Pretty much yes. That is clearly reflected in the price difference.
 

Offline hwj-d

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #582 on: July 29, 2019, 11:38:22 am »
But the very most of them you can do with dmm6500 and scancard too?  :popcorn:
A K2000 or DMM6500 with scan card is effectively a DAQ, unless I'm missing something.
Yes. One can use other and more scancards (Firmware). But the measuring, triggersystem and possibilities is apparently identical?
 

Offline Hugoneus

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #583 on: July 29, 2019, 12:55:50 pm »
Some more information for you guys! :)

You can watch the video here: [48 Minutes]

youtu.be/Lezd27BzQLo
What took you that long ;) nice to get some extra example of configuring a trigger and yes FFT please :)
...

I have been so busy and this poor instrument was waiting for review.

Review videos honestly take the most time. I can do two or even three repair videos in a weekend, but reviews can take many days. I have to make sure I do the instrument justice and highlight its strengths and weaknesses in a fair and relevant way by designing experiments, study data sheet and since nothing is scripted I have to make sure I am not being verbose at all.
« Last Edit: July 29, 2019, 12:57:38 pm by Hugoneus »
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #584 on: July 29, 2019, 03:18:43 pm »
I couldn't justify the extra price for the DAQ6510 + Cards though, most of it is present in the DMM6500 and I would probably not use the cards very often assuming I would buy one.
edit: Also the DMM6500 has a 10A input at the back while the DAQ6510 is limited to 3A with a high burden voltage.

Yes, I couldn't justify the price difference at the time either when I picked up the DMM6500.

The 7700 series scan cards are obviously more versatile.  The 7700 card having both a CJT and 2x relays dedicated for up to 3A current.  The 2000-SCAN also has two relays for current measurement but they are 1A max, and can only be used with shunt resistors to measure the voltage drop (so no actual direct current measurement as far as I can tell).

For the most part I was happy with the DMM6500 since you had the option to do simultaneous V/I measurements, although there is a serious flaw with that either in hardware or software (not sure which since Keithley went dead silent after I pointed it out to them). I can only guess its in the hardware, but who knows since they won't discuss it.

Either way I became a bit more interested in picking up a scan card, but obviously prefer something like a 7700 card over the 2000-SCAN.  Regardless, I don't see myself buying a DAQ6510 any time soon and the DMM7510 doesn't share the V/I measurement flaw that the DMM6500 has, so I'm content for the most part.  Maybe one day I will get the DAQ, but it would be next year time frame at the earliest (if at all).
 

Online MegaVolt

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #585 on: July 29, 2019, 05:23:38 pm »
although there is a serious flaw with that either in hardware or software (not sure which since Keithley went dead silent after I pointed it out to them). I can only guess its in the hardware, but who knows since they won't discuss it.
Could you clarify the details of this problem?
 

Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #586 on: July 29, 2019, 05:49:12 pm »
Could you clarify the details of this problem?

Sure.  I mentioned it a 2-3 pages back, but here is the setup and pics below.  This occurs on the 100V range when the circuit is setup to perform simultaneous V/I measurement.  The larger the current in the circuit, the greater the effect.  I chose 9V as the source to make it easy to switch between the 10V and 100V ranges.  I use a 10R power resistor so the current is high, but not high enough to force me to use the 3A range (although the effect in the 3A/10A ranges are the same).

Basic Setup:
-Manually select DCA Range of 1A
-Manually select DCV Range of 10V
-Auto Impedance or 10M impedance is fine

Simple Circuit:
797844-0

DMM6500 on 10V/1A Ranges:
797850-1

DMM6500 on 100V/1A Ranges (Notice the large unexplained voltage drop):
797856-2

For comparison:

DMM7510 on 10V/1A Ranges:
797862-3

DMM7510 on 100V/1A Ranges (No large voltage drop):
797868-4

You don't have to use the exact values I did for the test circuit, but the more current through the circuit the better, since at very small currents you will not see much of a difference.  Try it with even larger voltages/current and see larger drops that can't be explained solely by burden voltage.

Keithley originally tried to blame my power supply as the problem.  But then I showed them the results using a battery.  They have been silent ever since.  I even asked if I should send my DMM6550 in for warranty work, and they wouldn't even respond to that.  I technically don't even know if it is just my specific DMM6550 that is the problem, but Keithley complete silence is not reassuring.

Edit: All I do is swap the test leads between the DMM6500 and DMM7510, no other changes are made.
« Last Edit: July 30, 2019, 01:36:15 pm by JxR »
 
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Online MegaVolt

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #587 on: July 29, 2019, 06:05:55 pm »
here is the setup and pics below.
How exactly do you connect the device?
For 6500 there is a limit: "Sense terminals on inputs are limited to 10 V range during ratio measurement."
 

Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #588 on: July 29, 2019, 06:08:36 pm »
here is the setup and pics below.
How exactly do you connect the device?
For 6500 there is a limit: "Sense terminals on inputs are limited to 10 V range during ratio measurement."

No sense terminals are used.  The circuit diagram shows the connection points, and the polarity of the measurements in the pictures confirms which terminals I used.

Here are some pics.  Hopefully the wire colors make it clearer.
« Last Edit: July 29, 2019, 06:22:38 pm by JxR »
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #589 on: July 29, 2019, 06:37:10 pm »
I would love if someone else could confirm my findings, since I still really don't know if it is just isolated to my particular unit.  There really is nothing I can find to explain the behavior, and my test setup is identical between two different meters.

Also, there is of course no problem measuring current or voltage separately (meaning either a connection to the Amp input or to the HI input, but not both simultaneously).
 

Offline Hugoneus

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #590 on: July 29, 2019, 06:45:55 pm »
here is the setup and pics below.
How exactly do you connect the device?
For 6500 there is a limit: "Sense terminals on inputs are limited to 10 V range during ratio measurement."

No sense terminals are used.  The circuit diagram shows the connection points, and the polarity of the measurements in the pictures confirms which terminals I used.

Here are some pics.  Hopefully the wire colors make it clearer.

I will try this with the DAQ tonight.
 
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Offline Hugoneus

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #591 on: July 30, 2019, 01:47:24 am »
I tried the same thing as your setup. Both with a battery and with a power supply. I could not replicate the issue. The instrument reports the correct results.
 
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Offline cozdas

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #592 on: July 30, 2019, 01:58:04 am »
I would love if someone else could confirm my findings, since I still really don't know if it is just isolated to my particular unit.  There really is nothing I can find to explain the behavior, and my test setup is identical between two different meters.

Also, there is of course no problem measuring current or voltage separately (meaning either a connection to the Amp input or to the HI input, but not both simultaneously).

I wonder if this has something to do with the relay timings and/or measurement delays. Have you tried with different integration times (NPLC, repeat filters etc)?
 

Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #593 on: July 30, 2019, 03:18:30 am »
I wonder if this has something to do with the relay timings and/or measurement delays. Have you tried with different integration times (NPLC, repeat filters etc)?

There are no relays switching during the testing, except when you manually choose the 100V range (no relay switching occurs on the 1A/3A/10A ranges with simultaneous measurements).  NPLC/filter has no effect.  You do not have to technically even be doing a simultaneous measurement,  it will occur only measuring voltage.  But the circuit has to be wired up to do a simultaneous V/I measurement: Common LO, amp input near the low side of circuit, HI input where appropriate.  Anyways, alot of people here have actual DMM6500, and it is a simple enough circuit to duplicate.

It can of course be done using a power supply and electronic load as well, just better to make sure you are pulling around 1A or above.  It is not really apparent at all if you are only drawing say 1mA.
« Last Edit: July 30, 2019, 01:34:25 pm by JxR »
 

Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #594 on: July 30, 2019, 03:22:04 am »
I tried the same thing as your setup. Both with a battery and with a power supply. I could not replicate the issue. The instrument reports the correct results.

Dr. Shahriar, your pictures both show 10V range, and it only occurs when you select the 100V range.  Did you happen to try manually going to the 100V range?  I really appreciate you trying this out.
 

Offline maxwell3e10

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #595 on: July 30, 2019, 03:56:19 am »
Very strange! Can you check (with a separate meter across the battery) if  DMM6500 is reporting incorrect voltage? Presumably that is the case since the current does not change as you switch the voltage range.

If so, it could be a error in their switch matrix for different ranges. My guess: 100V range usually gets divided by 100 before ADC, so the actual voltage measured is about 0.09V. Somehow a fraction of the current burden voltage gets subtracted from it.
« Last Edit: July 30, 2019, 04:15:23 am by maxwell3e10 »
 

Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #596 on: July 30, 2019, 04:16:06 am »
Very strange! Can you check (with a separate meter across the battery) if  DMM6500 is reporting incorrect voltage? Presumably that is the case since the current does not change as you switch the voltage range.

If so, it could be a error in their switch matrix for different ranges.

Yes this has already been done with 3 different meters.  Only the DMM6500 that is doing the simultaneous measurement shows the problem.

Anyways here is an example using two SMUs to source 15V and sink ~1A, the DMM6500 to do a simultaneous measurement, and the DMM7510 to measure the voltage.  Same problem occurs with only the DMM6500.

798360-0
« Last Edit: July 30, 2019, 01:34:06 pm by JxR »
 
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Offline maxwell3e10

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #597 on: July 30, 2019, 04:24:26 am »
Thanks. Its clear that  either your meter has a bad FET or Keithley screwed up this fairly basic configuration.
 
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Offline cozdas

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #598 on: July 30, 2019, 05:05:08 am »
There are no relays switching during the testing, except when you manually choose the 100V range (no relay switching occurs on the 1A/3A/10A ranges with simultaneous measurements).  NPLC/filter has no effect.  You do not have to technically even be doing a simultaneous measurement,  it will occur only measuring voltage.  But the circuit has to be wired up to do a simultaneous V/I measurement: Common LO, amp input near the low side of circuit, HI input where appropriate.  Anyways, alot of people here have actual DMM6550, and it is a simple enough circuit to duplicate.

It can of course be done using a power supply and electronic load as well, just better to make sure you are pulling around 1A or above.  It is not really apparent at all if you are only drawing say 1mA.

I see. I don't have DMM6550, I only have DMM6500 but tried a similar setup with it (I used separate current and voltage sources).

I see the same problem: In DC voltage mode if you pass some current through the amps-common connectors, the voltage is misreported. Passing 1A through the amps terminal causes ~ -45mV error in voltage measurement in 10V range, and ~-2.6V error in 100V and 1000V ranges. Halving the current causes the voltage measurement error to halve too.

There seems to be a cross-talk from amps circuit in voltage mode indeed.
 
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Offline JxR

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Re: New Keithley DMM6500 and now DAQ6510
« Reply #599 on: July 30, 2019, 05:09:50 am »
I see the same problem: In DC voltage mode if you pass some current through the amps-common connectors, the voltage is misreported. Passing 1A through the amps terminal causes ~ -45mV error in voltage measurement in 10V range, and ~-2.6V error in 100V and 1000V ranges. Halving the current causes the voltage measurement error to halve too.

There seems to be a cross-talk from amps circuit in voltage mode indeed.

Thank you.  I really appreciate you confirming this for me.  My guess is that Keithley knows something is wrong as well, but the lawyers are not allowing them to talk to us about it.  Still it would be nice to have a couple more people confirm the same problem with their units as well.
 
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