New Keithley DMM6500 and now DAQ6510

[Wintel]

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?

[HendriXML]

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)

[HKJ]

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.

[KedasProbe]

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.

[HendriXML]

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.

[Kleinstein]

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.

[JxR]

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.

[gamalot]

DMM6500. Datasheet :

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

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

It’s not easy to put the wrong name on the USB port and network port.　

[HendriXML]

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.

[JxR]

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.

[Mr. Scram]

Great to see Keithley active on the forums again. I much appreciate manufacturers showing an interest in their customers.

[2N3055]

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..

[HKJ]

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.

[HendriXML]

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.

[JxR]

Firmware 1.7.0 for the DMM6500 is now available!

Release notes here: https://download.tek.com/software/supporting_files/DMM6500-FRP-v1_7_0_November_2019_RNs_DMM6500-FRP-V1.7.0.pdf

[JxR]

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.

[KedasProbe]

Nice I will try it tomorrow.
FYI it's not under Downloads but under Technical Documents & Software tab (on the same page)

[thm_w]

Link if anyone had trouble finding it: https://www.tek.com/digital-multimeter/dmm6500-6-1-2-digit-graphical-touchscreen-digital-multimeter/dmm6500-software-3

[Bugsyson]

Looks like us Canadians will have to wait, till after the US long weekend.

[gamalot]

Looks like us Canadians will have to wait, till after the US long weekend.

I can download it in Australia without any problem. 

[KedasProbe]

Some quick first impressions:
- The values on graphs still are not made for humans!
(in manual mode give us more step settings than 1,10,100,etc for Y-axis if you can't program it right, like 1,2,5,10, etc. or just give us Ymin and Ymax to set via script I can figure out to make it right)
- Average Y between cursors on display is not using the buffer values but the screen resolution values. (result changes when you zoom in/out)
- I got a blue screen when pressing 'analog edge trigger' in the graph menu, I cannot reproduce it.
(haven't played with the buffer sizes yet)

- There is a "measure config list" added, to group your measure settings, so you don't have to make a script for it.
Looks nice and more convenient, you can also check the settings before using it.

I didn't notice any other obvious changes (some font spacing fixed.)

[HighVoltage]

My first quick impression of the new firmware v1.7 for the DMM7510 and DMM6500:

1. Much better vertical graph scaling readability
2. Menu structure and positioning of touch screen keys are much more equal between DMM6500 and DMM7510

This seems to be a very good firmware update so far.

[JxR]

Is that very last pic really from the DMM6500?  Seems like it gained a digit of resolution.

[HighVoltage]

Here are 3 more screen shots from the DMM6500 (ENTER+HOME)

I really like the way they have made the menus and graphical layouts between the DMM6500 and DMM7510 the same now.

[HighVoltage]

I had the DMM6500 hooked up to a very stable LTZ1000A output.
The problem that was noticed before, with a sudden jump in the graph is still happening.

So, most likely this is a hardware problem and can not be solved in the firmware?