PXI 5611

Hi,
I have a set of RFSG with PXI 5611 as the RF signal generator. What types of antenna should I choose for the port of "RF out" at pxi 5611? Should I provide DC power for it? Do I have an option to control the DC output at RF out port of PXI 5611?
Thanks

Hello Long,
For deciding on an active or passive antenna, we need to know the transmit power need for the wireless communication to work properly. Looking at the specifications of the PXIe-5673 on page 21, the maximum output power is Noise Floor (-152dBm/Hz) to 10dBm. What is the maximum output power need for transmitting your signal?
If you need more power, we have a RF amplifier, PXI-5691 8GHz Programmable Amplifer, that can output up to 24dBm. Will this be enough output power to transmit your signal? If it is, a passive antenna can then be used for your applicaiton.
Even though the PXI-5691 provides a lot of flexibility, it might not be the best option for your application if you just need a fixed gain. For this case a active antenna would be a better option. Again, like I said above, it will be imperative to ensure that the impedances are matched. Looking at the VSWR specs for the PXIe-5673 on page 22, it states how much reflections you can have due to impedance mismatch.
I hope this helps you with selecting a passive or active antenna.
Jim St
National Instruments
RF Product Support Engineer

Similar Messages

I want to cascade two NI PXIe 5611 to make 2 upconverters statges for baseband signal

i want to cascade two NI PXIe 5611 to make 2 upconverters statges for baseband signal

Hello,
Could you please elaborate a bit on the application?
The PXIe-5611 RF Upconverter uses differential, baseband IQ signals as the input, applying quadrature modulation and upconversion to achieve a modulated RF output. If you are looking to cascade two in series, that would mean feeding a single ended RF output from the first stage into the baseband, differential IQ inputs in a second stage, which doesn't make sense to me. Perhaps we can find another solution to your application if we know some more details...
Regards,
Andy Hinde
RF Systems Engineer
National Instruments

I want the specification manual for NI PXIe 5611

i want the specification manual for NI PXIe 5611

You can adjust the PXI-5610 IF input signal to fall between 15-35 MHz. The IF input range of the PXI-5610 cannot be changed from this 15-35 MHz span.
The PXI-5610 would be controlled via calls to the NI-RFSG instrument driver for NI's RF signal generator products.
There is no PXI-5610 only manual. The PXI-5610 is part of NI's PXI-5670, 5671, and 5672 2.7 GHz RF signal generators, whose manuals are available here:
http://sine.ni.com/nips/cds/nisearchservlet?nistype=psrelcon&nid=13478&lang=en&q=FQL:%28%28nilangs:e...
Regards,
Andy Hinde
RF Systems Engineer
National Instruments

Is there any limitation for PXI 5670 to generate QPSK signal?

Hi,
I would like to select PXI 5670 to generate the QPSK signal in my system. How does is it make the QPSK modulation?As I understand, QPSK modulation would need to have two AWG to generate the I and Q signal. See below:
But PXI 5670 only integrated one AWG (PXI 5421). So how does it make the QPSK modulation?
Do I need to download the user−specified baseband IQ waveform into the memory first,then playback it to generate the IQ signal and then upconvert it to the desired QPSK signal? if yes, the playback time will be limited by the onboard memory size. Even if I select the one of 256 MB of onboard memory , it can only 1.28 seconds of waveform data at the default sample clock rate of 100 MS/s. Does it means the QPSK signal can only apear within 1.28 seconds? That's definitely not enough for me.
I am not sure if my understanding is correct or not. Any reply is appreciated.
BR,
Ivan Chen
Solved!
Go to Solution.

Hello Ivan.Chen,
This is correct given the PXIe-5611 performs the complex modulation and direct upconversion in the physical analog domain. Typically, you will still be generating your waveform in software based upon I and Q however. The real I waveform will be generated on channel 0, and the real Q waveform will be generated on channel 1. The I and Q analog waveforms will then be modulated in a quadrature fashion and generated at the appropriate RF frequency.
The fundamental difference between the PXI-5670 and PXIe-5673 is that your the PXI-5670 eventually needs to received a waveform at full rate (100 MS/s) which has already been complex modulated while the PXIe-5673 only requires two real waveforms, I & Q, which can be at streamed to the device at a decimated rate since the onboard signal processing supports interpolation. This allows the PXIe-5673 to be an ideal streaming platform. It is also much faster in regards to tuning, and is capable of a 4x instantaneous bandwidth improvement - the PXI-5670 is 20 MHz, while the PXIe-5673 is > 100 MHz in bandwidth.
Check out the specifications for the PXIe-5673 for more detail on the overall device, as well as the PXIe-5450 specifications for more detail on the onboard signal processing capabilities.
Chris Behnke
Sr. RF Engineer
High Frequency Measurements

5450 Test Panel error

Hello,
I am trying to execute a vi using PXIe 1065 with NI 5673 RFSG and NI 5663 RFSA. When I try to test NI 5450, using MAX, it passes self test but upon clicking the Test Panel and running it using start, the sine wave isn't running and I donot get an amber light on the device's LED? Also after some time i get the timeout error!
Please help.
Regards,
prads

Hi Prads,
First, make sure you have configured the PXIe-5611 Properties page, setting the PXI-5652 as the LO source and the PXIe-5450 as the baseband arb.
Next, make sure there is a cable running from the PXI-5652 REF IN/OUT to the PXIe-5450 CLK IN, assuming you are not trying to lock the PXIe-5673 to an external 10 MHz reference.
Also try running self teston each of the three individual modules, and try Test Panels on the PXI-5652 and PXIe-5450 individually to see what happens.
Let us know what you find. Also, if you can post a screenshot of the error if you are still receiving one that would help.
Thanks,
Andy Hinde, MBA
Systems Engineering - RF
National Instruments

NiScope error list for ni5142 (what is over fetching error?)

For a PXI-5142 digitizer,
I have implemented some sample code using simulation drivers (in C), it runs smoothly with simulation but when I run my program with actual hardware after some time I get this error in NI SPY:
> 2238. niScope_FetchComplexBinary16 (Digitizer, "0", 0, 256, {0x0000,0x0000,...}, {0x00,0x00,...})
> Process ID: 0x00000B98 Thread ID: 0x00000BC4
> Start Time: 12:18:05.062 Call Duration 00:00:00.063
> Status: 0xBFFA4018
And the description is :
The requested data has been over fetching.
Status Code: -200004
1- What does over fetching mean? Am I fetching too fast or too slow? Is this a warning or an error?
2- Where can I find a document describing all possible error messages for different devices (PXI-5142, PXI-5600, PXI-5441, PXI-5610, PXI-5611, PXI-5450, and many other that we have) with more detail?
Thanks in advance

Hi dashesy,
You will get this error when the data requested has been overwritten in the device memory. when Onboard device memory overflows. Because of system and/or bus-bandwidth limitations, the driver could not read data from the device fast enough to keep up with the device throughput.
Reduce your sample rate, alter the data transfer method (from interrupts to DMA), use a product with more onboard memory, or reduce the number of programs your computer is executing concurrently.
Hope this helps,
sunil

Trans-receiver system using PXI

Hi,
I need to build a trans-receiver system using PXI. For the transmission part I can use a PXI 5652 to generate a single tone continuous waveform.
For the receiver part, I need an antenna to capture the signal transmitted by 5652 (which will have a transmission antenna ). The received signal will then be down converted by PXI 5601 (RF OUT of 5652 is connected to LO IN of 5601). The intermediate frequency will be then digitized by PXI 5622 (IF OUT of 5601 is connected to IF IN of 5622).
But my question is these connections are already there between the slots/chassis.(The next stage has I/Q demodulation but I want to get clear on this part first). But there is not output port on the PXI 5622, so how can I check the digitized output?
I have attached a file for reference.
Thanks,
Sharmi
Attachments:
Ref.docx ‏689 KB

Hi Sharmi,
To address your questions:
Is the data, after it is down converted and digitized by the 5622 is automatically sent to 5450?
No, the data is not automatically sent to the 5450. The digitized data is sent to the backplane and can be accessed on your controller/laptop through LabVIEW or the RFSA Soft Front Panel. The 5450 is used to take digital signals generated by LabVIEW and turn them into an analog signal. It is not used in any part of the downconversion process.
If you want to take the data that you receive from your 5663 VSA and send it to your 5673 VSG, you will need to do so using software. There are RFSA and RFSG examples that ship with the driver that you can use as a starting point on how to acquire a signal and send a signal using LabVIEW. These examples can be found by going to Start » All Programs » National Instruments » NI-RFSA (or NI-RFSG for generation examples) » Examples.
5450 has “400 MS/s I/Q Signal Generator” written on it, so does it generate I and Q channel data separately?
The 5450 does generate IQ data on 2 separate channels. LabVIEW is used to generate an IQ bit stream. The IQ data is combined after being upconverted with the 5611.
Also 5611 has “I/Q Vector Modulator” written. So, can it demodulate a signal (after it is split into I and Q components by 5450) and then combine the resultant output?
The 5611 is an upconverter and is used to take the IQ signals generated by the 5450, combine them, upconvert them from some IF frequency to an RF frequency and transmit them. It can be used to do some basic types of modulation, but not demodulation. The NI RF Signal Generators Help ( Start » All Programs » National Instruments » NI-RFSG » Documentation) has a section about the 5611 that includes the hardware block diagram and a more detailed explanation about each part of the block diagram. This is where you can find out more about what basic types of modulation the 5611 is capable of performing.
Let me know if you have more questions, I'd be happy to help.
Sarah Y
SDR Product Manager
National Instruments | Ettus Research

Runnig RFSG Pulsed Data.vi on PXI-5652

HI .
I am trying to run RFSG Pulsed Data.vi on pxi 5652 but i keep gettin the error "niRFSG Configure Generation Mode.vi<ERR>Invalid value for parameter or property."...how can i resolve it .......and my other question is that wether this card is capable of generating arbitrary waveform......
I am new to this card although i did take the hands on course available on the net but i am not familiar with all the block till now.
I also change the parameters in the VI but nothing work .
help needed
thnx
Regards

Hi,
The reason you are seeing this error is because this example is only compatible with the 567x devices. Running this example with the 5652 will not work because it is not meant for this type of application. You need to have an arbitrary waveform to create the IQ signal and then an upconverter to convert the signal to RF. I would recommend to review the manual and specifications for the 5652 to understand the full functionality of the device. The 5652 is stated as being a continuous-wave RF signal generator signal generator with modulation capability. Do you have any other modules in your system?
PXI-5652 Support Page
http://sine.ni.com/psp/app/doc/p/id/psp-582/lang/en
There are specific examples that are dedicated to just the 5652 but there are no examples of generating arbitrary waveforms. We have specific function generators that are for that purpose. The 5673 for example is comprised of 5450, 5611 and 5652. The 5450 is what produces the I and Q signal to the Upconverter (5611). The 5652 provides the LO signal to the 5611 which upconverts the IQ signal to RF.
What other devices do you have in your system? What is the overall application? If you are just starting out and want to see the functionality of the 5652 I would recommend to check out the 5652 examples in the NI Example Finder (Help>>Find Examples, search 5652).
Regards,
Regards,
Jordan F
National Instruments

Poor PXI IO performance on Latitude E6410 with ExpressCard 8360

Hello,
I have a Dell Latitude E6410 with a Core-i5 M520 which is giving me very poor io performance when using an ExpressCard 8360 card to connect to a PXI Rack.
The sustained IO rate that I can get appears to be about 1/3 of that that I can get using the same ExpressCard on a Dell Latitude E6400 (with a Core2Duo processor).
I am using the A05 bios (latest at time of writing) on the E6410.
Wade.

I am running Windows XP (32 bit) sp3 in both cases.
The E6410 has 4GByte of memory fitted.
The E6400 has 2GByte of memory fitted.
I have also use the same ExpressCard 8360 via a PXIe to ExpressCard Adaptor in a Desktop machine with similar performance figures to the E6400 - i.e. much better than the E6410.
The Desktop Machine is an HP Compaq D7900 with 4GByte of memory, Core2Duo E8500 also running Windows XP sp3 (32 bit).
Also, on the Desktop, I am running NI PXI Platform Services 2.3.2 and NI-Visa runtime version 4.3.
On the E6410, I am running NI PXI Platform Services 2.5.2 and NI-Visa runtime version 4.6.
I no longer have access to the E6400 so I am not sure what sofware versions were installed. However, they are unlikely to be new than the versions installed on the E6410.
Wade.

Choosing a PXIe controller for streaming 200 MBps

Warning: This is a long post with several questions. My appologies in advance.
I am a physics professor at a small liberal-arts college, and will be replacing a very old multi-channel analyzer for doing basic gamma-ray spectroscopy. I would like to get a complete PXI system for maximum flexability. Hopefully this configuration could be used for a lot of other experiments such as pulsed NMR. But the most demanding role of the equipment would be gamma-ray spectroscopy, so I'll focus on that.
For this, I will need to be measuring either the maximum height of an electrical pulse, or (more often) the integrated voltage of the pulse. Pulses are typically 500 ns wide (at half maximum), and between roughly 2-200 mV without a preamp and up to 10V after the preamp. With the PXI-5122 I don't think I'll need a preamp (better timing information and simpler pedagogy). A 100 MHz sampling rate would give me at least 50 samples over the main portion of the peak, and about 300 samples over the entire range of integration. This should be plenty if not a bit of overkill.
My main questions are related to finding a long-term solution, and keeping up with the high data rate. I'm mostly convinced that I want the NI PXIe-5122 digitizer board, and the cheapest (8-slot) PXIe chassis. But I don't know what controller to use, or software environment (LabView / LabWindows / homebrew C++). This system will likely run about $15,000, which is more than my department's yearly budget. I have special funds to accomplish this now, but I want to minimize any future expenses in maintenance and updates.
The pulses to be measured arrive at random intervals, so performance will be best when I can still measure the heights or areas of pulses arriving in short succession. Obviously if two pulses overlap, I have to get clever and probably ignore them both. But I want to minimize dead time - the time after one pulse arrives that I become receptive to the next one. Dead times of less than 2 or 3 microseconds would be nice.
I can imagine two general approaches. One is to trigger on a pulse and have about a 3 us (or longer) readout window. There could be a little bit of pileup inspection to tell if I happen to be seeing the beginning of a second pulse after the one responsible for the trigger. Then I probably have to wait for some kind of re-arming time of the digitizer before it's ready to trigger on another pulse. Hopefully this time is short, 1 or 2 us. Is it? I don't see this in the spec sheet unless it's equivalent to minimum holdoff (2 us). For experiments with low rates of pulses, this seems like the easiest approach.
The other possibility is to stream data to the host computer, and somehow process the data as it rolls in. For high rate experiments, this would be a better mode of operation if the computer can keep up. For several minutes of continuous data collection, I cannot rely on buffering the entire sample in memory. I could stream to a RAID, but it's too expensive and I want to get feedback in real time as pulses are collected.
With this in mind, what would you recommend for a controller? The three choices that seem most reasonable to me are getting an embedded controller running Windows (or Linux?), an embedded controller running Labview real-time OS, or a fast interface card like the PCIe8371 and a powerful desktop PC. If all options are workable, which one would give me the lowest cost of upgrades over the next decade or so? I like the idea of a real-time embedded controller because I believe any run-of-the-mill desktop PC (whatever IT gives us) could connect and run the user interface including data display and higher-level analysis. Is that correct? But I am unsure of the life-span of an embedded controller, and am a little wary of the increased cost and need for periodic updates. How are real-time OS upgrades handled? Are they necessary? Real-time sounds nice and all that, but in reality I do not need to process the data stream in a real-time environment. It's just the computer and the digitizer board (not a control system), and both should buffer data very nicely. Is there a raw performance difference between the two OSes available for embedded controllers?
As for live processing of the streaming data, is this even possible? I'm not thinking very precisely about this (would really have to just try and find out), but it seems like it could possibly work on a a 2 GHz dual-core system. It would have to handle 200 MBps, but the data processing is extremely simple. For example one thread could mark the beginnings and ends of pulses, and do simple pile-up inspection. Another thread could integrate the pulses (no curve fitting or interpolation necessary, just simple addition) and store results in a table or list. Naievely, I'd have not quite 20 clock cycles per sample. It would be tight. Maybe just getting the data into the CPU cache is prohibitively slow. I'm not really even knowledgeable enough to make a reasonable guess. If it were possible, I would imagine that I would need to code it in LabWindows CVI and not LabView. That's not a big problem, but does anyone else have a good read on this? I have experience with C/C++, and some with LabView, but not LabWindows (yet).
What are my options if this system doesn't work out? The return policy is somewhat unfriendly, as 30 days may pass quickly as I struggle with the system while teaching full time. I'll have some student help and eventually a few long days over the summer. An alternative system could be built around XIA's Pixie-4 digitizer, which should mostly just work out of the box. I prefer somewhat the NI PXI-5122 solution because it's cheaper, better performance, has much more flexability, and suffers less from vendor lock-in. XIA's software is proprietary and very costly. If support ends or XIA gets bought out, I could be left with yet another legacy system. Bad.
The Pixie-4 does the peak detection and integration in hardware (FPGAs I think) so computing requirements are minimal. But again I prefer the flexibility of the NI digitizers. I would, however, be very interested if data from something as fast as the 5122 could be streamed into an FPGA-based DSP module. I haven't been able to find such a module yet. Any suggestions?
Otherwise, am I on the right track in general on this kind of system, or badly mistaken about some issue? Just want some reassurance before taking the plunge.

drnikitin,
The reason you did not find the spec for the rearm time for
the 5133 is because the USB-5133 is not capable of multi-record acquisition. The rearm time is a spec for the reference
trigger, and that trigger is used when fetching the next record. So every time you want to do another fetch
you will have to stop and restart your task.
To grab a lot of data increase your minimum record size. Keep in mind that you have 4MB of on board
memory per channel.
Since you will only be able to fetch 1 record at a time,
there really isn’t a way to use streaming.
When you call fetch, it will transfer the amount of data you specify to
PC memory through the USB port (up to 12 MB/s for USB 2.0 – Idealy).
Topher C,
We do have a Digitizer that has onboard signal processing
(OSP), which would be quicker than performing post processing. It is
the NI 5142
and can perform the following signal
processing functions. It is
essentially a 5122 but with built in OSP.
It may be a little out of your price range, but it may be worth a
look.
For more
information on streaming take a look at these two links (if you havn’t
already).
High-Speed
Data Streaming: Programming and Benchmarks
Streaming Options for PXI
Express
When dealing with different LabVIEW versions
it is important to note that previous versions will be compatible with new
versions; such as going from 8.0 to 8.5.
Keep in mind that if you go too far back then LabVIEW may complain, but
you still may be able to run your VI. If
you have a newer version going to an older version then we do have options in
LabVIEW to save your VI for older versions.
It’s usually just 1 version back, but in LabVIEW 8.5 you can save for
LabVIEW 8.2 and 8.0.
ESD,
Here is the link
I was referring to earlier about DMA transfers. DMA is actually done every time you call a
fetch or read function in LabVIEW or CVI (through NI-SCOPE).
Topher C and ESD,
LabVIEW is a combination of a compiled
language and an interpreted language.
Whenever you make a change to the block diagram LabVIEW compiles
itself. This way when you hit run, it is
ready to execute. During execution LabVIEW
uses the run-time engine to reference shared libraries (such as dll’s). Take a look at this DevZone article about
how LabVIEW compiles it’s block diagram (user code).
I hope all of this information helps!
Ryan N
National Instruments
Application Engineer
ni.com/support

Convert PXIe-8135 controller to dual-boot Windows 7 and LabVIEW RT

Hello. I have a PXIe-8135 controller that originally was just running Windows 7. We are trying to convert it to a dual boot system to also run LabView Real Time. (There is host computer that will run LabVIEW 2014 with the RT module, and the controller will become a target).
I have created a FAT32 partition on the hard drive of the controller. Now, I’m trying to install the real-time OS with a USB flash drive made using the MAX utility, but I cannot boot using the USB drive for some reason. I keep getting the message “waiting for USB device to initialize”.
In BIOS, legacy USB support is [ENABLED] and boot configuration is set to [Windows/other OS]. I’ve tried removing the drive, waiting, and reinserting. I’ve tried two different USB drives (both 8 GB, different brands).
I’m not sure what to do next. Apart from the USB boot issue, is converting the PXIe-8135 even possible? I read about SATA/PATA hard drive issues with older controllers, but I don't know about this one.
Thanks, in advance, for your help!
-Jeff
Solved!
Go to Solution.

Per Siana's licensing comment, more information on purchasing a deployment license if you do not have one for this target can be found here.
The RT Utility USB key is used to set up non-NI hardware with LabVIEW Real-Time, but you should not need it in this situation to convert to dual-boot (*). Try this:
1. Since you already have a FAT32 partion created, go into BIOS setup and change to booting 'LabVIEW RT'.
2. The system will attempt to boot LabVIEW RT, see that the partition is empty, and switch over into LabVIEW RT Safe Mode. (this safemode is built into the firmware, which is why you don't really need the USB key).
3. The system should come up correctly and be detectable from MAX, and you can proceed with installing software.
4. To switch back to Windows, go back to BIOS setup and choose 'Windows/Other OS'
(*) One area where the USB key is helpful on a dual boot system is with formatting the disk. If you want to convert from FAT32 to Reliance on the partition designated for LabVIEW RT, the USB key lets you attempt to format a single parition and leave the rest of the disk untouched. If you format from MAX, the standard behavior is to format only one RT partition if found, but if not found, it will format the entire disk. Formatting from MAX on a dual boot system is consequently riskier and you could lose your Windows partition.

Start and Stop Trigger using PXI-6120 and DigitalStartAndStopTrigger.vi not working :-(

Hello,
I've been trying for a while now to get my PXI unit to capture a waveform between a Start and Stop (Reference) Trigger using the NI example DigitalStartAndStopTrigger.vi downloaded from the NI website. However, whilst the start trigger and stop trigger seem to be working i.e. the VI runs and stops at the correct times there is never any data read from my DAQmx compatible PXI-6120 card. So I can see the VI is running around the aquisition loop but the Property Node AvailSampPerChan is always returning zero... this has me slightly puzzled. I thought this might just be a driver issue so I've updated my box to the following software versions (see below) and installed the latest drivers e.g. DCDNov07.exe (also from the NI site) but nothing has changed.
my software as of now.
Labview 7.1 (with the 7.1.1 upgrade applied)
Max 4.3.0.49152
DAQmx 8.6.0f12
Trad DAQ 7.4.4f7
before I updated I had the same problem but with the following versions:
Labview 7.1 (with the 7.1.1 upgrade applied)
Max 4.2.1.3001
DAQmx 8.5.0f5
Trad DAQ 6.9.3f4
So to cut a long story short I still have the same problem with the triggers... does anybody have any ideas what is going wrong?
To add insult to injury it the traditional DAQ example ai_start-stop_d-trig.vi was almost working correctly before I did the upgrade. It had the strange behaviour of capturing the AI0 channel but on the wrong edges (e.g. if I set Start on Rise and Stop on Fall it would do the opposite, Start on Fall and Stop on Rise).
I'm going to leave my box doing a mass compile over night but i'd really like it if someone could suggest a solution or point me in the right direction.
Many thanks,
Mike

Hi Graham
I'm out of the lab today but I'll try and answer your questions as best I can...
1) What are the values you have set for Buffer size, Rate, samples per read and post trigger Samples?
At the moment I have all the values (e.g. sample rate, buffer size etc) unchanged apart from the ones I mentioned in my previous post (see above). I have in the past played around with changing the buffer sizes and rates in the example VI but as this appeared to have no effect on the behaviour I now have them setup as in the download.
2) Does the program end after the stop trigger is implemented?
Yep, if I toggle the trigger line high then low I see the program exits the read loop and the VI stops running as expected.
3) Lastly can you give me the details of triggering method. Are you
using a digital train of users set digital pulses? how long is the
program running.I'm using the WriteDigChan.vi to manually toggle the first digital line of the PXI-6733 card which is wired directly to PFI0 of the PXI-6120 card. Generally, I just start the VI running and then toggle the line high, wait a couple of seconds and then toggle it low.
To me it all looks like it should be acquiring samples but as I said yesterday it just refuses to fill the buffer with any data (and hence no samples are read).
Any ideas? and thanks for you help,
Mike

Trouble capturing waveform from PXI-4472

I'm really a very green newbie at this stuff, so bear with me...
I've got a PXI-4472 data acquisition board and a PXI-5411 waveform generator. I've connected the arbitrary out of the 5411 to the channel 0 in on the 4472. An external oscilloscope shows a 1v-amplitude sine wave being generated.
I created a very simple VI to show what the 4472 is capturing. It connects a NI-DAQ channel I generated to the standard "AI Acquire Waveform.vi", then out to a Waveform Chart, all within a while loop with a Stop button. Problem is, all the waveform chart seems to be showing is the running average of the waveform instead of the form itself (solid line, a tad above zero).
I can hook the 4472 input channel up to a DC-out power supply, a
nd when I vary the voltage, the waveform chart changes as well.
So my question (whew!): What's wrong here that's not allowing me to capture a waveform from the 4472 (in turn from the 5411) and display it on my waveform chart?
Thanks in advance for the help.

Never mind.... it was a sample rate problem. I upped the sample rate and it came out ok.

Triggerring PXI-4110 to measure 1 current value while HSDIO PXI-6552 generating waveform

Hi,
Some question about PXI-4110 to measure current while PXI-6552 is generating the waveform.
1. Let say, I need to measure 3 points of current values, i.e. while PXI-6552 is generating sample-1000, 2000 and 3500. On the edge of sample 1000,2000 and 3500, the PXI-6552 will send a pulse via PFI line or via PXI backplane trigger line. My question is, is it possible to trigger PXI-4110 (hardware trigger or software trigger) to measure current values at these points ?
2. Let say I need to measure the current on 0ms (start of waveform generation by PXI-6552) , 1ms, 2ms, 3ms, 4ms... and so on for 1000 points of measurement, code diagram as shown at the figure below. It is possible for the VI "niDCPower Measure Multiple" to measure exactly at 1ms, 2ms, 3ms .. ? How much time will have to spend to complete acquire 1 point of measurement by "niDCPower Measure Multiple" ?
Thanks for viewing this post. Your advice on hardware used or software method is much appreciated. Thanks in advance.
Message Edited by engwei on 02-02-2009 04:24 AM
Attachments:
[email protected] ‏46 KB

Hi engwei,
1. Unfortunately, the 4110 does not support hardware triggering. Therefore you cannot implement direct triggering through the backplane or anything like that. However, there are a couple of possible workarounds you can try:
a) Use software triggering: Say your 6552 is generating in one while loop, and your 4110 is to measure in another while loop. You can use a software syncrhonization method like notifiers to send a notification to your 4110 loop when your 6552 has generated the desired sample. This method, however, will not be very deterministic because the delay between the trigger and the response depends on your processor speed and load. Therefore, if you have other applications running in the background (like antivirus) it will increase the delay.
b) Use hardware triggering on another device: If you have another device that supports hardware triggering (like maybe an M-series multifunction DAQ module), you can configure this device to be triggered by a signal from the 6552, perform a very quick task (like a very short finite acquisition) then immediately execute the DCPower VI to perform the measurement. The trigger can be configured to be re-triggerable for multiple usage. This will most likely have a smaller time delay then the first option, but there will still be a delay (the time it takes to perform the short finite acquisiton on the M-series). Please refer to the attached screenshot for an idea of how to implement this.
2. To make your 4110 measure at specific time intervals, you can use one of the methods discussed above. As for how long it will take to acquire 1 measurement point, you may find this link helpful: http://zone.ni.com/devzone/cda/tut/p/id/7034
This article is meant for the PXI-4130 but the 4110 has the same maximum sampling rate (3 kHz) and so the section discussing the speed should apply for both devices.
Under the Software Measurement Rate section, it is stated that the default behavior of the VI is to take an average of 10 samples. This corresponds to a maximum sampling rate of 300 samples/second. However, if you configure it to not do averaging (take only 1 sample) then the maximum rate of 3000 samples/second can be achieved.
It is also important to note that your program can only achieve this maximum sampling rate if your software loop takes less time to execute than the actual physical sampling. For example, if you want to sample at 3000 samples/second, that means that taking one sample takes 1/3000 seconds or 333 microseconds. If you software execution time is less than 333 microseconds, then you can achieve this maximum rate (because the speed is limited by the hardware, not the software). However, if your software takes more than 333 microseconds to execute, then the software loop time will define the maximum sampling rate you can get, which will be lower than 3000 samples/second.
I hope this answers your question.
Best regards,
Vern Yew
Applications Engineer, NI ASEAN
Best regards,
Vern Yew
Applications Engineer
Attachments:
untitled.JPG ‏18 KB

Problems performing offset null and shunt calibration in NI PXI-4220

I am using a 350 ohm strain gage for the measurements, i have already create a task in MAX, when i want to perform offset null in the task, the program shows a waiting bar and the leds in the 4220 board start to tilting, but when the waiting bar stops, MAX gets blocked. it has been impossible to me to perform the offset null, what can i try?.
which will be the correct values for the parameters beside the gage parameters for the strain measures?

Hello,
Thank you for contacting National Instruments.
Usually when this problem occurs, it is do to incorrect task configuration or incorrectly matched quarter bridge completion resistor. Ensure that you have the correct Strain Configuration chosen. The default is Full Bridge I. If you only have a single strain gauge in your configuration, you will need to change your configuration. Also ensure that if your are using a quarter bridge completion resistor make sure that it is 350Ohm not 120Ohm. If the resistor if 120Ohm you will more thank likely not be able to null your bridge.
Please see the PXI-4220 User Manual for more information about your configuration and signal connections: http://digital.ni.com/manuals.nsf/websearch/F93CCA9A0B4BA19B86256D60
0066CD03?OpenDocument&node=132100_US
Also, you can download and install the latest NI-DAQ 7.2 driver: http://digital.ni.com/softlib.nsf/websearch/50F76C287F531AA786256E7500634BE3?opendocument&node=132070_US
This 7.2 driver has a signal connections tab displayed when configuring your DAQmx Task which show you how to correctly connect your signals.
Regards,
Bill B
Applications Engineer
National Instruments

PXI 5611

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