4-wire resistance measurement with 3706 DMM using 3721-ST plug-in card

Hi,
I am new to labview and trying to get a 4-wire resistance measuremnt . I am kooking for an example program to get a 4-wire resistance measurement using a 3721-ST card on a 3706 Keithley DMM. I have one program where I always get error -1074000000. Thanks a lot for your inputs.
Best,
Chander

As you should be able to determine with Help>Explain Error, it's an instrument error query failure. See if you can run the error query in MAX.
You did not specify where you got the driver or attach the code. The only driver I found was from Keithley. If this is the driver you are using, you should ask them about their code.

Similar Messages

Why is the PXI-2575 not recommended for 2-wire resistance measurements?

The spec for the NI PXI/PXIe-2575 says "Note The NI PXI/PXIe-25-75 is not recommended for 2-wire resistance measurements". Why is this? If I want to perform 2-wire resistance measurements, what would be a good alternative?

It really depends on your measurement. The problem with 2-wire resistance measurements is that the resistance of the wiring and the switch path will be included in your measurement. If you are measuring in the kOhms to MOhms, this should be neglible. But measuring anything smaller will add a large error. That is why 4-wire resistance measurements are recommended. The sense lines can measure the voltage across the part you actually want to measure and an accurate measurement can be made.
This is true for all switches.
My philosophy is to use 4-wire measurements except when checking for an open.
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What's the difference between 4-wire and 2 wire resistance measurements w/ 9219?

It appears that the NI-9219 provides a small current in either 4-wire or 2-wire resistance measurement mode. What is the difference between the two methods? Just accuracy?
Also, if I am measuring the resistance of a solenoid (when it is not excited) using either method above, do I need some type of shunt resistor or do I just litteraly just wire HI/LO and EX+/EX- across the solenoid terminals?
Thanks!

Resistance thermometer wiring configurations:
Two-wire configuration
The simplest resistance thermometer configuration uses two wires. It is only used when high accuracy is not required as the resistance of the connecting wires is always included with that of the sensor leading to errors in the signal. This applies equally to balanced bridge and fixed bridge system.
Three-wire configuration
In order to minimize the effects of the lead resistances a three wire configuration can be used. Using this method the two leads to the sensor are on adjoining arms, there is a lead resistance in each arm of the bridge and therefore the lead resistance is cancelled out. High quality connection cables should be used for this type of configuration because an assumption is made that the two lead resistances are the same.
Four-wire configuration
The four wire resistance thermometer configuration even further increases the accuracy and reliability of the resistance being measured. In the diagram above a standard two terminal RTD is used with another pair of wires to form an additional loop that cancels out the lead resistance. The above Wheatstone bridge method uses a little more copper wire and is not a perfect solution. Below is a better alternative configuration four-wire Kelvin connection that should be used in all RTDs. It provides full cancellation of spurious effects and cable resistance of up to 15 Ω can be handled. Actually in four wire measurement the resistance error due to lead wire resistance is zero.
Message Edited by JoeLabView on 10-24-2008 01:00 PM

What is a 4-wire resistance measurement?

I'm developing a Labview user interface for setting up analog input channels. AI Config.vi has a measurement mode input cluster that includes a 4-wire ohms option. I hate to admit it but I don't know what that is, when one would want to use it, or how. Can anyone enlighten me?

4-wire resistance measurements are used when you need either very-high accuracy, or the measurement leads are very long. The way a normal 2-wire resistance measurement works is that a fixed current is passed through the resistance being measured and the meter reads the voltage drop across the unknown resistance, and Ohm's law allows the meter to calculate the resistance. The problem is that this technique read the total resistance (including the test leads and any connection resistance).
A 4-Wire resistance measurement uses seperate sets of leads for applying the current to the unknown resistance and for measuring the voltage drop across the resistance. This gives very accurate measurements because the sense inputs to the meter have very very high impedence,
resulting in very very small current flow through the sense leads. Thanks again to Ohm's law, very very small current flow means very very small voltage drop in the wires, resulting in very very small measurement error--regardless of how long the measurement leads are.
Or at least that's the theory.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

AC resistivity measurement with MyDAQ on TEC

Hello,
I would like to ask for advice: we would like to measure resisitivity of Peltier-elements. If we use DC method, because of the Seebeck-voltage of the element, we do not get the real resistivity value. The common method to use AC measurement in case of such devices. I would like to know, if it is possible to use a MyDAQ device for this task? As a first approach we do not need the best accuracy, this would be more as a "broken-element" test (there is usually a significant shift away from the nominal AC resistivity value stated by the manufacturer).
What would be the easiest way to carry out a simple measurement? What about if I use one analogue output of the MyDAQ lets say with 1kHz, and I drive the Peltier-element with this voltage AC source? And I connect a known resistor in series, and I measure the AC voltage drop on this. From this data, I could calculate the current, and the AC resistance of the Peltier-element? Of course I have to choose a resistor so the MyDAQ can drive the network.
what is your opinion, where to start?
Thanks!
Solved!
Go to Solution.

Hello, thanks for the reply!
Actually I am just going to replace 60 Peltier elements in a "home-made" 15 years old heat exchanger (I expect to find some mice too ). This assembly has dropped performance (heat transfer power) and also I know that, a few years ago after a malfunction with the hot side cooling fans, this device was running for a certain time without forced cooling. What is quite bad in case of Peltier-elements. I have already bought 65 brand new Peltier-modules and after I get some heat conducting paste, I will replace them. And I will have 60 pieces of old Peltier modules, to play with them
Since I have this NI MyDAQ, I thought it would be fun (and would give also valuable information) to try to measure the old elements' AC resistivity. Since this task is not like I should do often, so for first, I would not like to go for more pro solutions, I will try the MyDAQ first.
I expect that some of the modules got structural degradation during the heat shock, and this may be measurable in a shifted AC resistance.
I would do the measurement with zero applied DC voltage. These modules are Melcor PT3-12-30L (discontinued product), the nominal module resistance is about 5 Ohm.
EDIT: and would you recommend a certain circuit to try? Shell I use a known resistor for current measurement via measuring the voltage on it? Or I could use a known AC current to drive the Peltier, and I would measure the resulted AC Voltage on it?

4 wire resistance with HP34401A takes 600ms for 1 measure! run faster?

Hi everyone,
I am using an HP 34401A Multimeter ( through RS 232 ) to make a 4 wire resistance measure every 1000ms (very precisely). However each measure takes roughly 600 ms...Consequently, I don't know when that measure is made (at ,...,300, 400, ...ms?).
Would anybody know how I could solve this problem? Like for example letting the multimeter refresh the measurement as farst as it can ( intern trigger) and labview just reading the value every 1000ms...? However the measurement would still take 600ms ( I suppose ) ....
Any help would be great,
Marc
PS : If the HP trigger is software and the while loop set to go as farst as possible I can get a measure every 600 ms....
Lowing the precision doesn't make the measure go faster....
If the HP trigger is "internal" and the while loop set to 1 sec(or as quick as possible) the while loop takes 2000 ms....
Attachments:
HP VI.vi ‏40 KB

Hi,
It is not useful to create several subjects for the same problem (http://forums.ni.com/ni/board/message?board.id=170&message.id=211603)
I think that it is nor useful ti use the "control mode.vi" at each time. You need to configure it only one time.
You also can try to modify your instrument driver and to delete unused functions which take time. More things you write or read to the serial port, more time it will take.
Hope this helps
Manuel R
AE dans une autre vie

4 wire resistance

I need to check the resistance on a joint weld. I am using a PXI system running in LabView. I need to add this test to the exsisting program.
1. Use a 4 wire resistance meter such as an HP 34420A Nano0ohmeter.
2. Put the meter on 4 wire resistance measurement mode and set to the most
sensitive scale.
3. Connect the current injection leads to heater pins 1 and 7.
4. Connect the voltage measurement leads to heater pins 8 and C1.
5. Measure the resistance.
Any suggestions???

Here you find an instrument driver for your HP 34420A.
Since I do not know the instrument itself I don't know if the connections will be ok.
Waldemar
Message Edited by Support on 04-24-2007 10:47 AM
Waldemar
Using 7.1.1, 8.5.1, 8.6.1, 2009 on XP and RT
Don't forget to give Kudos to good answers and/or questions

HAS any one used a 50 ch DMM for resistance measurement?

What i'm trying to do is simple, i'm trying to monitor 50 channels or should i say 50 points of resistance measurement and then datalogging a change but i have a restriction and that is the sampling rate. i can't use a realy since there is a DEBOUNCE issue so i'm stuck right now on this. i have to pretty much scan a 50 channels in 20uS or less and then logg everything that changes. please help thanks.

Hi CrukZ,
I am NOT a "hardware" person, but recently researched this subject and (with a hardware person) built a shorts-test station. One solution that I/we considered was to use an analog DAQ board. We'd have put some voltage - say 5V - on a buss, then branched off the buss with 50 individual high-precision resistors - one to each testpoint (one input goes straight to the ?V buss). The DAQ board does a single-ended voltage measurement at each test-point - the mid-point of a voltage-divider - and use the measured voltage to calculate current and/so resistance. Two 1.25MHz DAQ boards (triggered together), at 25-channels each, would get the DAQ-rate you're after.
You'd have to play with the test-voltage and resistor choices depending on the current/voltage specs of your device. I think the closer the series resistor matches expected DUT resistance, the better it is for the calcs, but then really low resistance means higher current so it's "a balancing act". The more expected resistance varies, the worse it is for the calcs.
In our case, the tested circuits included diodes and current didN'T change linearly with test-voltage. However, we successfully emulated a hand-held Fluke DMM @1.2V on the 400 ohm scale. Done-deal!
BTW, I won't feel bad if someone describes why this is a terrible idea.
I am NOT a hardware guy person
When they give imbeciles handicap-parking, I won't have so far to walk!

Continuity measurement with keithley 3706

Hi,
I'm a new user and i'm having some basic dificulties with a Keithley 3706 system switch/multimeter and two 3723 boards and i'm programming it using LabView.
I have to measure continuity and insulation of 31 pins. Explaining better, i have one plug with 31 male pins, and other plug with 31 female pins, that goes on tools, and i have to be sure that each line is continue and insulated from each other.
The continuity part i made using :
2 Poles configuration, measuring resistance with 2 wire ohms funcions, so i puted each male pin in the channels 1 to 31(high), and each female pin in the channels 61 to 91(low). Then i can close the channel that i want and see that is ok.
But now i have to compare one channel to each other. I readed a about this and a i believe that i have to chance the configuration to four wire ohms. But i'm not sure, so my questions are:
Can i do insulation checks within the two wire ohms function? How can i tell the system for example to measure from the ch01 HIGH to ch02 high, or low... is there any way?
If not, How can i do this in the four wire configuration, reminder that i have two 3723 boards? As you can see i'm a realy new user with this kind of system. I didn't found any clue in the manual that comes with the system.
Thanks,
Francisco

Hi Fransisco,
First off, I'm glad to hear that you were already able to test for continuity on one channel. To do this I imagine you are setting one mux to to channel 1 (which would be one side of your cable) with the common going to the HIGH of the DMM) and the second mux to channel 1 (which would be the other side of your cable) with its common going to the LOW of the DMM).
For your insulation measurement are you still looking for a resistance measurement? If so, then you can connect your first mux to channel 1, and the second mux to channel 2. This would measure the resistance from the first wire to the second wire. You should not need to use a four wire measurement to do that.
If that is not what you want to do please let us know,
Eric S.
AE Specialist | Global Support
National Instruments

Scanning with external DMM with Agilent 34970A using Labview

Hi,
I am a relatively inexperienced user of Labview. I have written a VI to
scan several channels on a 34970A using the 34901A multiplexer module
to take voltage readings. I want to use a more accurate DMM than the
internal one however so I have hooked up a Fluke 8840A to the agilent
and I want the scanner to simply switch between the channels while the
fluke actually takes the voltage measurements. How do I modify my
existing VI so that it uses an external DMM? One of the driver VI's is
'configure external instrument' which i assume is the obvious option
but i'm not sure where to insert this to modify the VI.
Thanks
Tom

What you do kind of depends on the capabilities of the external DMM and how fancy you want to get. If you at the section called 'Scanning With an External Instrument', you'll see how the connections can be made for an automatic scan. The 34970 will issue a trigger to the external instrument and when the measurement is complete, the instrument will send a signal back to the 34970 to close the next relay in the scan list. If you can do this, then the Conf Exteranl Instrument would replace the Conf Scan List and Conf Scan functions in the Advanced Scan Example. I'm not sure about the Conf Trigger but I suspect you would need to set slightly different parameters for that. The Read function would have to be replaced with a read of your external instrument. Some additional functionality may have to be added to take a reading after each relay closure if the DMM cannot save a series of measurements.
I had to once use an external instrument and didn't do any of this. The external instrument did not have external triggering or a an output that could be used to advance the scan so I just used the HP34970 Switch function to close a relay exclusively and a dmm read inside a for loop. I created an array of channels and the for loop auto-indexed them. This was simpler to program but the scan took a bit longer than what is described in the manual.
Message Edited by Dennis Knutson on 08-31-2006 07:47 AM
Attachments:
34970 with External DMM.JPG ‏24 KB

How to use external timebase for Two Edge Separation measurement with PCIe 6351

Hi
I am working with PCIe 6351 x series DAQ card.
counter measurements.
Here i need to measure the time/no edges between two edges. Falling to Raising of two signals.
I got the measurement with internal time base.
here i need to synchronize the measurements with external clock from the external setup.
so i need to use that external clock,timebase for the counters.
Any solution please..
Regards,
Hari

First, the VI you mention is NOT for STC timer/counters. Therefore, it won't work.
If you want to get the time interval between two edges, you want to use the Functions -> Data Acquisition -> Counter -> Count Events or Time VI. This will do the function you are looking for.
Mark

Samples Not Acquired on NI 660x or NI 6624 Devices When using pulse width, semi-period or two-edge separation buffered measurements with the NI 660x and NI 6624 on counters 0 and 1, some samples may not be acquired under certain circumstances.

In the DAQmx 9.4 Readme the following is stated:
Samples Not Acquired on NI 660x or NI 6624 Devices When using pulse width, semi-period or two-edge separation buffered measurements with the NI 660x and NI 6624 on counters 0 and 1, some samples may not be acquired under certain circumstances.
Could anyone elaborate on this? I am particularly interested in knowing under what circumstances this problem arises for the 6602 PCI devices.
How should I understand 'NI 660x and NI 6624 on counters 0 and 1'. Is it only a problem on counter 0 and 1 for the 660x or does this only apply for the 6624 devices.
/mola

Are there any NI Product Support Engineers out there who has an answer to this question and who are willing to share it with me?

Flow Measurement With Turbine Flow Meter Using cFP

Hi I am trying to measure a flow rate using a Gems FT-110 Turbine Flow Rate Sensor. The cable connection has a Red one that says 5-24VDC, a Black one that says 0 VDC and a Brown one showing a square wave. If I am using a compact Fieldpoint, should I use a Counter like the NI cFP-CTR-500? How do I connect the flow meter to the module? Thank you.

This is a sourcing sensor. Look at Fig 3. in the manual .

NI-4060 giving invalid 1st reading after switching from or to LOW Resistance Measurements

We've been using TestStand & LabView to test various Circuit board. On series of test involves checking for a short circuit (Measure Low Resistance 4-wire) then measuring for a 3.5Vrms signal on another part of the board.
For each measurement, the following NI-DMM VI's are used in order:
niDMMInit, niDMMAutoZero, niDMMConfigure, niDMMMeasure, niDMMClose.
If we do the Low Resistance 4WR measurement, then a AC V measurement, the 1st reading from the DMM is approx 10x too high, if a 2nd reading it done it is then OK.
It doesn't matter how long a delay is before we take the 1st measurement, it's always approx a factor of 1E+1 out.
If however we don't do a Low Restance prior to
the AC V measurement, then the measurement is always correct.
I expermented with turning AutoZero on & off, and various resolution settings, however none of these seem to have an effect on the result.
Can anyone explain these strange results?
Thanks
Simon Holman
Simon Holman
Software Engineer
Certified LabVIEW Developer
Certified TestStand Developer
measX GmbH & Co. KG.
http://www.measx.com

Thanks, after playing with a few more settings I found if I turned the Cacheing off niDMMInitWithOptions, with "Cache=0" that everything worked fine, but it would take a couple of seconds to get the first AC measurement after switching from resistance.
Simon
Simon Holman
Software Engineer
Certified LabVIEW Developer
Certified TestStand Developer
measX GmbH & Co. KG.
http://www.measx.com

Current Voltage measurements with Agilent B2912A

Hi
I am new to LabVIEW and have to do IV measurements with Agilent B2912A sourcemeter. I want to do sweep mode and want to save measured current values in a .lvm file. Is there someone who could help me writing a simple LabVIEW VI?
Thanks in advance.

I'm going to copy/paste your pdf into the thread to make things easier to read:
I wanna control (sweep Voltage in a certain range and measure corresponding current)
Agilent B2912A SMU through this LabVIEW. Please find VI in attachment. Here I tried to
modify an example, provided by Agilent, to get IV measurements. Unfortunately there are
two little things which I can not find a way to do, i.e.,
1- I want to put a time control between each successive applied voltage value, in sweep
mode. At the moment, as I het run all voltage values (defined in the sweep range) run with
the speed of computer's serial/USB read clock (I guess, means it is very fast). I want to
put a delay (user defined) after each voltage is applied and current is measured. One
thing that bothers me is this "Fetch Measurements" sub-VI in CASE STRUCTURE fetches all
readings at once, couldn't find alternative sub-VI in the provided library/drivers from
Agilent.
2- How can I measure current, voltage and resistance with respected to time (not rendom
time but corrsponding to measuring time); like measured current versus time, Resistance
versus time.
Many thanks in advance.
Windows introduces some error into timing of while loops. How precise of a time control are you looking for? It sounds like you don't need timing to be TOO precise as you didn't start by worrying about timing. If this is the case, you should be able to add the Wait (ms) into your loop to add whatever delay you'd like.
In terms of displaying several data sets, you likely want to look at using the XY-graph with multiple plots. This has been discussed many times. One of those discussions can be found here: http://forums.ni.com/t5/LabVIEW/How-can-I-plot-multiple-curves-using-the-XY-graph/td-p/252597
Keep in mind that's an old thread so you're unlikely to get replies in that thread.
Working to understand that example and adding the Wait (ms) should help you find your solution.
Jeff B.
Applications Engineer
National Instruments

4-wire resistance measurement with 3706 DMM using 3721-ST plug-in card

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