All of the JAT's VIs output results as "sequence" and "timestamp", eg. the "Max and Min Voltage.vi".
I use the JAT to analyze high speed differential signals with unit interval of just 300ps. Because of this, the timestamp output cannot meet the required resolution. However, if timestamp is replaced with double precision float, it should be able to.
I have brought this up with NI's tech support and this is what they recommend, which is to suggest this change over here.
This is pretty trivial to achieve through LabVIEW itself, but...
Signal Express is a simple, stand alone data acquisition system that allows those with limited exposure to LabVIEW set up simple test and measurement routines. One area where this is ideal - at least, for me - is in environmental or long life testing. Instead of crafting a beautiful piece of custom software for my colleagues, I can hand them a DAQ, point them in the direction of the SignalExpress and DAQmx installers, and off they go. With a little fiddling, they can create a logger that suits their needs.
One thing I've noticed, however, is that when sampling with non-simultaneous cards such as the USB 6225, users will select 1-pt-on-demand, set to some big interval, and then come back screaming at the top of their lungs - "OHMYGOD THERE'S CROSSTALK BETWEEN CHANNELS!". With a little bit of fault-finding, it's easy to point out that it's not crosstalk, but ghosting between channels, because I would guess that 1-pt-on-demand uses interval sampling and rattles through the multiplexing as quickly as it can.
My idea: give users the option to either select round-robin mode with a sensible delay, or complete control over the interchannel delay.
I realise that the standard line is usually "use LabVIEW" - I do - but I'd rather spend my time working on the important stuff and empowering those with less experience and/or exposure to make accurate measurements.
I use a PXIe-6363 which a wonderful device. But it lacks level shifting at the digital I/O.
I would recommend that most DAQ multi-io devices support programmable and externally driven level-shifting for digital IOs. Range for DAC driven level-shift (0.8 - 3.6, 5V), and support for external input. It would also be nice if multiple ports are present that some of them allow independent logic levels. Default level should be 3.3V. Port configurable pull-up, pull-down and latch-hold.
It is not possible to build Kernelmodule nirlpk 2.0 on Kernel >= 3.10
if (create_proc_read_entry(nNIRLP_kDriverAlias, 0, nNIRLP_procDir, nNIRLP_procRead, NULL))
create_proc_read_entry appears to have been deprecated in kernel 3.10.
It would be nice to have the ability to spawn a “Child” Task based upon a “Parent” Task local virtual channels. Today, this can be accomplished with global virtual channels, but not easily with local virtual channels within the Task. Today, we dynamically generate Tasks based upon the physical channels and save it to an external file. There are many variations of this, but all require a decent amount of programming for complete automation. The external calibration interface in MAX has greatly improved over the years and now it is easy to calibrate multiple sensors at the same time. Not only that, but it is nice to have device setup and calibration information in one location.
DAQ Hardware like NI PCI-6225 has 8 Correlated DIO (port0) but 24 DIO are supported by DAQ Hardware.
It is not possible to use hardware timing on port1 or port2 outputs, they are not bufferd. Please expand
the buffered outputs also to port1 and port2 in M-Series DAQ Hardware to get 24 correlated DIO.
IMAQdx Timeout is a non settable property. It is fixed on 5s
When I do not trigger my camera for 5 seconds (and that is what I want regularly after aquisitions at 100FPS) , I get a timeout error.
Just ran into a situation where I need to stream a lot of data to TDMS. The only problem is that I need to store additional metadata with the channels. I could go through all of the generated TDMS files and insert them after the fact, but this is kind of tedius. I propose a way to add metadata to the channel. My first thought was to use a variant input on the Create DAQmx Channel, but some of the polymorphics already have really fully connector panes. So I am now thinking to just add a property to the Channel Property Node that is just a variant. When logging to TMDS, the variant attributes can be put in the metadata of the channel. Do something similar for the group so that we can have additional group metadata.
Metadata that I'm currently thinking about could include sensor serial number and calibration data. I'm sure there is plenty of other information we would like to store with the TDMS file.
At the new client.. no shock to many of you I "Get around"
I explained to some of my new compadres the DAQmx "Tasks" need to be created once.... Preferably during development!
I even created a new task in MAX using the DAQmx wizard, Dragged it to the LabVIEW project explorer and all of that!
I even went so far as to name the "AUX" temperature channel "armpit"- Trust me, after 5 minutes delivering a .lvproj based on the "Contineous measuement and logging (DAQmx) project template" it was impressive to the client that the plot "armpit" showed 37C on the chart. Guess where the thermocouple was.
So, Because I am that amazing, I showed them that they could Drag-n-Drop the Task to MAX and use MAX to monitor my armpit temperature. I even showed them that MAX could show them the wiring diagram!
"HOLD IT"! they said, The wiring diagram is right there! On SCREEN! per channel!
That is where I just about lost my mind! They wanted to see this connection diagram for another Channel--- that worked! BUT there was no way to output that wonderful data!
"Can I create a Wiring Diagram for this channel, device or task?" were the next words out of their mouths. I WAS STUNNED! "Not today" I said, "I'll post that excellent idea!"
It gets a bit annoying that PXI1Slot2 is listed after PXI1Slot14 when doing an ascii sort. I (ok, admittedly, my coworker) proposes having naming conventions that will allow for a better ascii sort. For instance, PXI1Slot002 PXI1Slot014.
I try to read data from SPS (SAIA SPS) with cgi technik. I have to read the values of 933 variables at the time.
I wrote a labview programm that you can find in Attachement. My problem ist, i can only read
170 values of the 933 values, i want, at the time.
Questions: Ist there a maximal numbers of variable to read or to write with Data socket at the time?
Thank you for your contribution
1. on page 2-4 of the manual (http://www.ni.com/pdf/manuals/375865a.pdf):
here is a sketch or a picture helpful to understand the text.
It is easier to understand page 2-4 with a small picture how to connect the AI SENSE for exapmle.
2. a terminal diagramm in the manual for each card (PXI, PCI) is also very helpful.
Alternatively a paper with the terminal diagramm to send with the devices.
Every time I have to work with a NI daq device the first thing i need to know is what pins can or cant do something.
Currently this involves looking through something like 7 diffrent documents to find little bits of information and bringing them back to your applicaiton.
A block diagram could easily be a refrence point for the rest of the documentation (you want to know about pin IO for your device look at this document)
Plus a good block diagram can tell you what you need to know quickly, and clearly. A picture is worth 1000 words?
Some might find the current documentation adiquite, but personally i would really like to have a block diagram that represents the internals and capiblities of the pins and device in general. Most Microcontrollers have this and it is an extremly useful tool. So why not have one for the Daq devices as well?
Hi Everyone. I have an old Kistler type 7001 pressure sensor and type 5007 charge amplifier and I'm going to use NI USB 6009 DAQ board to measure in-cylinder pressures of a single cylinder diesel engine.I'm very much new to Lab view and using all these sensors.Can some one kindly tell me how to start and I would be very grateful if someone could post a program (block diagram) to collect,convert the voltage to pressure and write the final output to a text file.Thanks alot in advance.
I use Daqmx a lot for writing .NET based measurement software.
Whereas the API itself is quite decent, the docs are horrible. Accessing them is convoluted at best, requiring the VS help viewer. Almost nothing is available online and decent examples are quite scarce, which will definitely be an issue for absolute beginners...
This definitely deserves some attention!
Including me, there are couple of other LabVIEW users, those wish to have this feature available, wherein we could be able to create Virtual channels (or even Global tasks) for an internal channel of a DAQ or SCXI.
This feature implementation should also include, allow to configure and use internal channels while using DAQ Assistant (though I personally don't prefer using DAQ Assistant).
Check this post here. This feature wish is around the same line.
Occasionally, I need to create global virtual channels that are used to acquire AC voltage signals. Currently, I just acquire the instantaneous values and take the RMS average in LabVIEW. However, this does not let you calibrate the global virtual channel in MAX (because the acquisition is the instantaneous DC voltage).
It would be nice to have the custom scales allow user customizable LabVIEW programming plug-ins, such as RMS average point by point, so that I can calibrate an AC voltage channel in MAX.
We use often the NI CompactDAQ 9234 for sound measurements.
Our standard microphones with iepe amplifier have a noise level of about 16 dB(A) and sensitivity of 40...50 mV/Pa.
The noise of the 9234 is about 50μV rms, corresponding to a sound level about 32 dB(A). So we can use this microphones only for measurement above 35 dB(A).
A better version of a card 9234 with 2 ranges 5V and 0.5 V would be very useful. The noise in the lower range should of course not exceed the range of 5...10 μV (12..18 dB(A)).
And many monitoring systems have only one Microphone, so we use only one channel of the 9234.
For this cases would be a lower priced one channel card OK.
A two channel card would be perfect: two channel measurement of one microphone signal in both ranges. The sound level program can measure from 20 dB(A) ... 136 dB peak without range switching.