differential vs nrse on ground referenced signals

Similar Questions

• Differential measurement across the ground of the card NOR referenced output.

  Hello guys,.

  I have a question, our pure curiosity.

  I use map of USB6212 to apply a sinusoidal signal of 10V to a game to the top, then measure the tension between charges.

  I'm attching here a simple diagram showing the system. The implementation can be modeled as a combination of RC - r series

  Note that I'm also measure voltage R2 in differential mode. Now that I am after is exact phase of monitoring between the two voltages (according to the RC and the R2).

  My question: is the correct diagram? I mean - is it OK to measure the voltage across R2 in differential mode with attached as such polarization resistors?

  It is one of the lines through R2 is already at AOGND. And AIGND and AOGNd are already connected inside the card, it will be then introduced errors?

  or does not at all?

  Thanks guys, will be grateful for a quick solution.

  You can do this but the differential mode does not have much.  Your signal source is single ended. The voltage at the terminals of R1 - C can be measured in different ways. It really is meaningless to measure the voltage across R2 differently because one end is connected to the Earth.  Polarization resistance, Rb, are not necessary in this case because the low enough impedance DC railways exist at all entrances.

  What I would do, is make two measures ended up alone.  AO1 measured on a single channel (AI0).  Measure the R1 - R2 junction on the other channel (AI1). Then the input voltage is AI0, the voltage at the terminals of R1 - C is AI0 - AI1, and the current is AI1/R2.  You will need to enjoy fast enough that the time between the different measures does not contribute too much to the phase error.  It depends on your frequency of signal and eligible errors.  Look at the charts of a waiting time to page 2 of the NI USB - 620 x specifications for more information on how to compromise between the speed, accuracy and multichannel source on measures resistance.

  Lynn

• Elvis II: FGEN, very fragmented signals low level

  We recently purchased some Elvis II platforms: very beautiful products.

  In any case, we have a problem with ANY when the amplitude is very small (about 10 ~ 30mVpp) signal (osserved on the scope) is really fragmented.

  We use as input AI1 (FGEN <->at the entrance to the quadrupole which is GROUND referenced) ed AI0 (output of the quadrupole, always referenced to GROUND)

  We have connected the two pins of AI (-) STILL common then to EARTH, while FGEN transits through the prototype Board.

  FGEN share the same GND AI?

  Where we are wrong?

  Thanks in advance

  Hi Parisi,

  I think that do you things in the right way. However, it is possible to see a bit of noise (which you see in your screenshot) for a lot of factor. In addition, Elvis II is a very useful and powerful but is not designed to operate small voltage.

  You saw the same behavior you acquire a significant voltage signal (more than 1 VP)

  Let me know

• Why do I get an offset with analog input

  
  

  Hello

  Thanks for posting your question on the forum.  I suspect that there may be a problem with
  the grounding.  I recommend looking through
  Developer Zone article, field wiring and analog noise considerations
  Signals, which describes in detail how to properly ground a signal.

  The important things to note are that you have a floating
  the source signal (unrelated to the construction on the ground) or an earthing and the
  setting input of your measurement (differential, referenced asymmetric,)
  non-references asymmetric).  For
  example, if you have a floating source and you try to measure the
  signal in differential mode, you must add two resistances (between
  10kOhms and 100kohms) to land correctly signal.  Resistance would HAVE + AI GND and
  other resistors would connect I - of AI GND.

  Post back with more details about your configuration of source and the input of the signal if you need more help.

• 6033 PCI analog measurement noise

  I want to assure you that I do everything I can to get the best measurement possible IM using a SCB-100; I use a card PCI 6033. I have connected my analog son Looking at a picture labeled e/s to 64 channel connector E series devices... I see to reason a choice AI GND, SENSE of HAVE it, HAVE SENSE 2, EXT REF, AO GND, D GND. I used the GND. HAVE My measure is close but there are a few milliamperes noise 4.30 should I get 4.80 on some units the extent of automation and I set up for single ref has ended and a 09:50 vdc extent I connected a wire to the GND AI for my units I measure power supply ground wire is short less than 10 inches, 16 gauge. I use the correct ground?. Thanks-Kurt

  This post is also in the forum of Labview, I think it belongs here.

  Kurt,

  Yes, it's good ground for a measurement of CSR.  Is your source of signal floating or grounded?  If it is connected to the Earth, I would recommend using differential or NRSE instead of CSR.  Here is a document that is an excellent reference for wiring and noise considerations.

  -Christina

• DAQ USB-6008 will be able to power and record voltage for UMS T5 blood pressure at the same time?

  I would use my NI USB-6008 to power my blood pressure monitor UMS T5 (http://www.ums-muc.de/en/products/tensiometer/t5.html) but also to take readings of it, but I don't know if it's possible to do it properly. The power supply for the instrument can be as low as 5V, I can easily get the dedicated + 5V channel. I'm able to feed the instrument and connect it to an analog input on the 6008 and measure a voltage in differential mode. However, when you read the documentation of support for the instrument, I find the following:

  "Potential pitfalls of data acquisition: the pressure transducer is configured in a full Wheatstone bridge, the input voltage and mV signal output can be connected to the same reference (mass)." Therefore, the mV output signal can be measured using a differential voltage measurement. Therefore, do not make an asymmetric measure of pressure transducer mV output. "(http://www.decagon.com/assets/Uploads/MeasuringUMSTensiometerswithnon-UMSControlandDataAcquisitionSystems.pdf)

  My understanding is that the 6008 can take a differential measure if I attach the signal '+' and the signal "-" to the analog inputs of positive and negative terminals. However, it seems that all the ports of ground on the 6008 are grounded to the same reference, which would make my measure of invalid tension according to the above paragraph. So my real question is: if I try to record the voltage with one of the analog inputs on the 6008 in this way, is the valid measurement? Or I need to find a separate power supply, with a different reference field to ensure that the measure is accurate?

  The technical details of this device is very poor. The manual is not much better. Companies that want to sell scientific equipment should publish decent cards or get out of business.

  In section 3.4.3 General requirements the device is described as a "bridge not amplified circuit.  This information along with the impedance of the bridge should be in the specifications, because it is essential to apply the device under any circumstances other than the nominal behavior in 10.6 V.

  The answer to your question is:

  You can use it with the box USB-6008.  The 5 V supply will result in output voltages a little less than half (5/10.6) the voltage specified in nominal conditions. You can use the differential input mode on the box USB-6008.  The absolute input voltages will be approximately 2.5 V with the 5 V power supply. This voltage is in the range of the aircraft. The differences are likely to be less than 100 mV. The resolution of the USB-6008 on the + /-1 V is located about 0.5 mV so your resolution of pressure will be about 1% of full scale. The voltage input impedance and termination of the USB-6008 will present a few errors.  These can be in the order of 5 to 10%. I can't predict much better without the missing bridge impedance specification.  These errors should be relatively constant and systematic. A calibration of the whole system - sensor and together hardware DAQ should allow you to compensate for a large part of this error.

  Lynn

• NEITHER USB-6221 SCB-68

  The acquisition of data USB-6221 unit is compatible with the SCB-68? I'm doing a number of analog in action<10V range="" with="" two="" of="" them="" being="" j="" type="" thermocouples="" and="" would="" like="" to="" have="" cjc="" capabilities. ="" in="" my="" quick="" glance="" at="" the="" scb-68="" page,="" and="" at="" the="" one="" for="" the="" 6221="" it="" isn't="">

  Thank you!

  Nope - you can scan through channels CSR or differential or NRSE... all in the same task (IE I 0-3 differential, CSR HAVE 4-6). The M series operating manual (/ book) shows how in the 'Earth-reference parameters in software AI configuration' section.

  see you soon,

  Andrew

• Computer laptop battery "in charge" but stuck at 0%

  Hello

  I have a G6-1b79ca Pavilion and the battery stopped charging.

  Windows show "Plugged in, load" and level to remain at 0%. Forever.

  Of course it is now completely empty.

  If I remove the CC of the computer plug, turn it off immediately.

  Here's what I did so far, more or less in that order:

  1. replace the battery (recommended by the logon page BIOS...)

  2 tried this popular patch:

  Stop-> remove battery and power cord-> hold down the button "POWER" 30 sec-> power supply DC-> Boot->-> battery-> uninstall Microsoft ACPI-Complient control method battery -> Shutdown-> put the battery in the Device Manager (cannot start on him alone because it does not... but maybe that might help)-> start the computer

  3. updated all the drivers and reinstalled all the HP utility (got the Intel drivers on the Intel site)

  4. I updated the BIOS with the latest version and reset to default settings

  5 tested the power supply with a multimeter (Psu unloaded, sleeve ground referenced outside it read 19.8V = internal plug, 18V centering PIN)

  6 replace the motherboard (which has already been replaced)

  7. replace the power supply

  8 reinstalled Windows

  9 weld the power directly to the motherboard adapter in order to bypass the connections all contacts (cut the CC Plug and soldered the bare wires directly on the pcb)

  The utility HP BIOS (F2 on startup) told me that the new battery fails the test and must be replaced. Awesome.

  The battery in the utility test assistant (run in Windows) HP tells me that the battery is OK, but would need to be loaded (Seriously? It becomes funny...)

  So basically the material is new.

  Utility Windows/HP tells me that the battery is OK, but the BIOS utility will tell me to replace it.

  What the hell is happening?

  The material is supposed to be (entirely replaced) A1 and windows were completely reinstalled.

  Any suggestion? My beginning of sanity to fade...

  On a side note, here is the situation that I hope not occurred:

  1. the original battery has failed

  2. he burned the motherboard charging circuit

  3. I replaced the battery then damaged mother burned load circuit card

  4. I finally replaced the motherboard that was damaged by the new battery, which was damaged by the previous motherboard, which was damaged by the original battery...

  5 return to square one, hundreds of $ less and a lot of time to lose...

  I can't buy ANOTHER motherboard/battery combo without going crazy...

  Thanks for any help!

  HE IS ALIVE! Lolll!

  The problem is the new battery, I don't know why, but it was completely empty and never had to charge.

  I ask the seller to replace and load a new a bit so I was able to start on battery only.

  I removed the power supply and the battery, which held the POWER button / 30 sec and started on the battery alone.

  Once in Windows I pluged the charger and now it is fully charged!

  Looks like the key here is to be able to start on battery alone. one thing I could never reach while struggling with that drained.

  This thread of hope help someone solve battery problems, because there are MANY possible solutions.

  Thanks to those who have taken their time to help!

• Great variation on thermocouple readings

  I have to type K thermocouples (two long wires twisted and welded at the end) connected to a map of SCC - 68 (without modules). This card connects to a data acquisition NI PXI-6221 multifunction with compensation of CYC.

  I have install a global channel virtual for the CCM, connected according to the diagram in the user manual, etc, etc-, that everything seems to work fine. When I connect my thermocouples, however, their readings are very sporadic; they could go from 69 degrees F up to 89 degrees F or more.

  Suggestions as to how I can get a more uniform reading? Honestly, I don't care if it jumps around a few degrees, but variations of 10 to 20 degree seem a bit much.

  I have attached a copy of my VI (LabVIEW 8.2) that I use to display temperatures (it's part of a larger system of control, so ignore everything except areas thermal two on the left ).

  Can be measured in differential mode?

  How the signal look like? UM, cleats, white noise?

  What about using a filter? Try fist: enjoy with 1kS/s and uses the average of 300 samples (work of 300ms for 50 Hz and 60 Hz power line noise)

• External and embedded parallel sampling

  Hello everyone,

  I made a simple example to show what I'm trying to achieve, but my problem comes down with a question: is it possible to have in parallel a task this channel to AI0 samples with the clock on board and another task this channel of AI1 samples with external clock source?

  In my application, I have
  (1) a single measurement task lets say pressure or temperature on a channel with the on-board clock
  (2) try a calculation of the frequency of the revolutions of the differential sensor (IRC)
  (3) a single signal of sampling of the task of the probe laser using the IRC signal as external source

  They are meant to operate in parallel

  2 + 3 works perfectly, but when I also add 1 I get the error-50103 occurred to DAQmx start Task.vi:1, is reserved for the specified resource. The operation could not be performed as indicated. Also 1 + 2 works perfectly together. Attached program - it's just quick example.

  Thank you very much

  Trying to create more than one task, the AI, the same time result in the encountered error message... This is because the AI can have only one example of clock source. As a result of access to the device, it is a sine qua non for a single device. Having more than one DAQ hardware will allow you to set two different clocks for both devices.

  hope this helps,

  Norbert

• NIDAQmxBase uses differential signals?

  I recently updated the NIDAQmx Base to the plus version and.  But now I'm a horrible corruption of my signals.  I checked with a scope and the signals are correct, but it sounds horrible crosstalk between channels.  The only thing I can think is that the Council does not truly differential switching beyond the first 8 channels.

  I use a card of 64 channels so there are 32 differential channels, I'm only using 16 channels beginning.  I use ' Dev1 / ai0:7, Dev1 / ai16:23 "for the specification of my channel.  The equipment works as the default "Datalogger" shows the correct data.  But I'm guessing that the data recorder was built with an earlier version of the basis of NIDAQmx.  This seems to happen when you use more than the first 8 channels.  This VI allows to work with the previous version of NIDAQmx base.

  Is this a known issue?

  Here's the code to initialize the jury NOR-6033

  

  Mac OS X 10.4.11 PPC / LV 8.5.1 / NIDAQmx Base 3.2.0 / VISA 4.4.0

  Hi Scott-

  I agree that relocation is the most appropriate next step.  I tried here with a very similar setup and I could get the correct number of samples during my reading, and accurate data looked.  Please let us know your results once the reinstallation completed.  Thank you-

  Ed

• create the differential signal of 6289

  Is is possible to create a sine wave of differential on the output of the 6289? And how can I do this.

  I created a differential DC 1V AO0 positive and negatives 1V AO1. Then measured on a differential input ADC signal, which is my DUT.

  Now, I'm cutting the CMRR and wanr to use the DAQ6289 because I don't want to add another piece of equipment for the test plan.

  Any ideas would be appreciated.

  Please take a look at this example to see how to generate out of phase sine waves:

  http://zone.NI.com/DevZone/CDA/EPD/p/ID/5001

  Have a great day!

  Daniel G.

  National Instruments

  www.NI.com/support

• Derives from NI USB 6363 signals (differential Setup)

  Hello!

  I just changed a task of data acquisition of 2 signals of "CSR" to "differential". After that, the signals set to reflect really bad. Did this happen because I have not yet hooked the acquisition of data the source of real tension? This loop is also simultaneously by sending output signals for data acquisition products. I'm just tests prior to the configuration.

  Thank you in advance.

  Yes.

  If you want you can connect the + 5v from the card to the channels if you want a real signal.  But with nothing hanging tension can walk around.

• How to connect dwyer SERIES 629 differential pressure transmitter to the acquisition of data 9219 and read the signal?

  Here is my sensor
  Pressure sensor

  Here's the DAQ data sheet:

  ACQUISITION OF DATA NOR 9219

  Here are my issues:

  First of all I don't know what is LO and HI exactly in the DAQ 9219 material.

  Second, I don't know what pin code I should connect the DAQ sensor signal wire. PIN 4 or 5 pin? The sensor has three pins, and I guess I should connect the other two wires to the power supply.
  Thirdly how to calibrate the sensor. In labview choose voltage in the wizard?

  I'm pretty new in this acquisition of data and I need your help.

  Thank you

  Hi SilasIII,

  Hmm well 3 sons are probably on the ground, the power and the return signal. The datasheet for the sensor says:

  

  First of all, you need to know which model you have (4-20mA, 0 - 5V or 0-10VDC). HI refers to the return signal, LO essentially means the land of the food that feeds the sensor. Then, you must get the 13-30 VDC supply. I don't think this should be too complicated and can be a simple wall DC power. You can learn how to create a custom in DAQmx scale. I hope that this is a starting point.

  Kind regards

  Eric

• Can I use differential ground with PXI-6704?

  
  

  The answer is no.

  I spent most of the day on the phone with engineers of NOR. The PXI-6704 manual provides conflicting information. Indeed, the PXI-6704 that she "can connect to a load that has a floating ground" operator, but it should also be mentioned that the load will no longer a floating ground, because the planes on the ground of the device are connected to the signal ground of the computer, which is connected to the Earth System. I don't know why the verbiage on floating to the ground is included because there is no way to isolate the load with this device.

  Our team regained the PXI devices OR. We have worked with the Application engineer spoke to R & D of clarification in the manual.