PXIe-4499 DAQmx Trigger

I'd like to trigger off a rising edge on one of the analog channels, let's say AI0, on a PXIe-4499 card however I can't seem to figure out how to specify the trigger source. I'm using the "DAQmx Trigger.vi" and the documentation says the following:
"source is the name of a virtual channel or terminal where there is an analog signal to use as the source of the trigger"
I tried creating a virtual channel with no luck and have looked through the 4499's documentation but haven't been able to find a reference to source names.
Can anybody offer a suggestion or point me in the direction of an example?

Hello bww,
The example you are looking for can be found on this page. The source you specify will be the signal that triggers the acquisition. This signal can come through the PFIO for your device, the PXIe chassis backplane, or the Analog Input channels. For your purpose (correct me if I am wrong) you want to acquire on AIO and begin the acquisition when the analog signal (AIO) is above a certain level? Then I would recommend configuring the example to look like the item below.
Regards,
Izzy O.
Applications Engineer
National Instruments
www.ni.com/support

Similar Messages

Differences in DAQmx Trigger (VI)

I am trying to figure out why DAQmx Trigger VI works differently with different hardware.
Case 1; using PXI-6133 and Reference Analog Edge version of VI
Case 2; using PXIe-6368 and Reference Digital Edge version of VI
My users have shown me that using an analog signal on an analog channel for a trigger source in both cases works. Now, using the same trigger source conditions, I want to use a PXI-6133 and Reference Digital Edge version of VI. This does not work. Why?
My goal is to create a subVI that will use the appropriate DAQmx Trigger VI, given the source trigger hardware. My application will aquire 2 sets of data simultaneously on different hardware. One set based on a trigger, one set continueuosly. Does this seem unreasonable?

TrigConfig.png - code from main VI that create parameters for Trigger
Setup Triggers.vi - subVI that configures Trigger
Kevins_Triggered Fast DAQ.vi - working VI for PXI-6133 and PXI1045
Attachments:
TrigConfig.png ‏177 KB
Setup Triggers.vi ‏39 KB
Kevins_Triggered Fast DAQ.vi ‏45 KB

Configure PXI-2567 to Trigger on Rising Edge using LabWindows/CVI

I need some help configuring the trigger edge for a PXI-2567 using Labwindows/CVI. I have been able to successfully create and execute a scan list using both the ni-switch and daqmx APIs. However, currently the PXI-2567 triggers on the falling edge of an input trigger. I need to configure it to trigger on the rising edge of an input trigger. Every function I could find in the daqmx API for configuring the trigger edge gave a non-fatal runtime error, and I could find no such functions in the ni-switch API.
Any help configuring the input trigger edge on the PXI-2567 using Labwindows/CVI would be appreciated.
Thanks

Hi JonRice,
You can configure the scan list to execute on the rising edge of an input trigger. Here are the Labwindows/CVI and LabVIEW functions you would want to use to retrieve, specify or verify the edge of a digital signal that advances to the next entry in a scan list.
NI-DAQmx C Property: More >> Advance >> Digital Edge >> Edge
You can get/set/reset this property using:
DAQmxGetDigEdgeAdvTrigEdge
DAQmxSetDigEdgeAdvTrigEdge
DAQmxResetDigEdgeAdvTrigEdge
NI-SWITCH C Attribute: NISWITCH_ATTR_TRIGGER_INPUT_POLARITY
You can get/set/check this attribute using:
niSwitch_GetAttributeViInt32
niSwitch_SetAttributeViInt32
niSwitch_CheckAttributeViInt32
NI-DAQmx LabVIEW Property: More:Advanceigital Edge:Edge
DAQmx Trigger Property Node
Short Name: Adv.DigEdge.Edge
NI-SWITCH LabVIEW Property: Trigger Input Polarity
niSwitch Property Node
Short Name: Trigger Input Polarity
Hope this helps! Let me know if you have further questions.
Chad Erickson
Switch Product Support Engineer
NI - USA

PXIe-4499 simultaneous samples multi-modules

Hello,
I have three PXIe-4499 simultaneous samples modules in a PXIe-1082 chassis.
I built a single AI voltage task which includes all the chnls on the three modules.
Do I need to do anything special to ensure all modules use the same sample clock?

Bert,
Channel expansion is by far the easiest way to synchronize channels in DAQmx. If all channels are in the same task they will share a sample clock and start simultaneously.

DAQmx Trigger Property Node in NI-9235

我使用DAQmx Trigger Property Node不會顯示Analog Edge
請問是否有辦法設定
DAQ設備為cDAQ-9172和NI 9235
另外想問
NI 9235有辦法設定量測到的數據在超過某個值後才開始紀錄數據

http://www.labviewpro.net/forum_post_detail.php?post=2010&fid=1
請先閱讀上面文章
再參考下面類似方法
http://digital.ni.com/public.nsf/allkb/4859504F14AF68DB8625721100640F26

PXI 4472 DAQmx Start VI taking a long time.

I have an issue with DAQmx Start taking up to a secoond to to execute and it's killing my cycle time.
I have a PXI 8360 with 3 PXI 4462's and 3 PXI 4472's. I configure DAQ Task and Commit at the begining of the sequence however every time i do a DAQmx Start it takes about a second to execute. I need to do about 5 in each Test sequence so it's eating up about 5 seconds of cycle time. I am using DAQmx 9.7.5 drivers and Labview 2013. We have the exact same hardware and software setup in another location but we are not seeing this issue there.
Any ideas what might be causing this would be appreciated.
Attachments:
DAMmx Start.png ‏4 KB

Hi Nathan,
I verified this by disabling the Start Task VI.
I've attached the commit code.
Thanks
Attachments:
PXI 4472 Acquire.png ‏8 KB
PXI 4472 and 4462 Commit.png ‏13 KB

DAQmx trigger AO from AI signal (error -200265)?

Here's my problem:
I have a PXI-6115 i/o card and I'm observing a waveform on ai0. When the waveform reaches a threshold, I want to generate a waveform on ao0. I tried looking at the example, "Cont Gen Voltage Wfm-Int Clk-Analog Start.vi," using ai0 as the trigger source but I get error 200265 (using an invalid trigger source). I realized that the channel should be in the task if I want to use it as a trigger, but I can't add an AI channel to an AO task, so I'm kind of stuck.
I've attached part of the code that I'm trying to use. Any advice would be greatly appreciated!
Attachments:
trigger_ao_from_ai.vi ‏50 KB

If your timing between Analog In and Analog Out is not critical, you could just use software triggering. Get your AO setup with Start Trigger set to None. Don't run it yet. Get your AI setup to read 1 sample. In a loop, put the AI read function. Each loop iteration should return one reading. When the reading goes below the threshold, call the AO Write function to send an output.
The trick is to not continuously call the AO write whenever the AI input is below the threshold, or it will be called on each loop iteration as long as the AI reading is below the threshold. You can use a shift register to hold a boolean flag. Drag down the shift register on the left side to create a previous state terminal. Send the threshold compare output to the shift register. On the left, you read both shift registers. Trigger the AO when the top terminal is True and the bottom terminal is False (using AND and NOT). This will trigger only once because on the next iteration, both will be True. The threshold compare will have to go to False and then True again before the next trigger will occur.
- tbob
Inventor of the WORM Global

Use Daqmx Trigger to initialize software

Hello,
I am using an NI PCIe-6537B to run an SMB-2163 High-Speed DIO Accessory. I have a high speed camera sending out triggers whenever a frame is captured. Each time the trigger is received into PFI4, a digital output (DIO#) sends out a waveform.
I would like to know if it is possible to read that trigger so that I can use it to trigger other things in the software "simultaneously."
I have attempted to simply read PFI4 as a digital input (Digital Bool 1 Line1 Point) while also using it as the external trigger. It worked for a while but after I left the project it now seems to only randomly read when the trigger is sent. Not knowing what changed since it last worked, am I doing this correctly or is there a better way to do this? Perhaps using the Daqmx events.
Any help is greatly appreciated!
Thanks,
Mike S.
CLAD

Hey Mike,
A couple of things here. Firstly, for the Change Detection timing type, you will not need to use the event structure in your program. This is implemented in hardware, with samples being latched when the configured lines show the change. Basically, every time the configured line changes, the DAQmx read will return the values of all lines configured for your channel.
Also, you will not be able to use PFI4 as the source for change detection. You will have to specify a data line (ports 0-3) for use with the change detection timing type. Here's some documentation I could find about using this:
http://www.ni.com/white-paper/4102/en/
http://digital.ni.com/public.nsf/allkb/4B9452520950566A86256F31006C9AEF

Daqmx Trigger Indication

How can I get an indication to the front panel that an acquisition event has triggered using Daqmx?
I've set the system to pretrigger on a falling edge, which works fine, however, the end user does not get an indication that the system has triggered until after Daqmx Read.vi has finished reading all the data.......12 seconds later (duration of acquisition event). I'd like the user to get the indication at the moment the trigger threshold parameters have been met.
I'm using LabVIEW 7.1, DAQmx 7.2.
Thanks.

I agree that a software trigger might be your best answer. I cannot think of a good way without additional hardware to indicate to the user the occurrence of a hardware reference trigger. The properties for available samples and total samples acquired will not give you the indication you are looking for with a reference trigger. These are valid options for a start trigger. If pretrigger samples are important to your application you can continuously read the samples into LabVIEW and programmatically determine the location you wish to trigger, saving your desired number of pretrigger samples and discarding the rest of the pretrigger data. There is an example already built for this in Help>>Find Examples by the name of "Cont Acq&Graph -Analog SW Trigger.vi".
Hope this helps,
Jennifer O.

NI PXIe 4141 source trigger for sequence start

Hi all,
Is it possible to use Source Trigger to generate a sequence in NI PXIe 4141 SMU? Whenever I try this only first and Second sequence voltages are produced and then sequence stops.
It seems to be waiting for Sequence Advance trigger. In this case what is the purpose of Source Trigger? can it only be used for single voltage transition?
I know I can use Start Trigger to start generat my whole sequence, but I don't want to do use it because it limits my capability to control Measurement using Measurement Trigger individually.
Please help!
Anandelamaran Duraisamy,
Senior Project Engineer,
Soliton Technologies (P) Ltd,
www.solitontech.com

Kevin:
Thanks for the info.
I have since added the ability to use the arm start trigger instead the start trigger, and it does what I was looking for.
>In practice, it seems that the "arm start" trigger is simply the one and only start trigger
>that can be configured for counter tasks.
Well, the regular start trigger works with output pulse tasks.
Which brings up another question: on a board with analog trigger circuitry, can you use an analog trigger for an task that accepts a regular start trigger? I don't seem to have a board with analog trigger, so I can't try it.
I find the documentation to be not as clear sometimes as it could be. I also find that it is often difficult to find the particular spot in the documentation where something is disscussed. That is partly because sometimes pieces of a given topic are scattered about.
Sure wish it was in a PDF so I could actually read through it!
John Weeks
WaveMetrics, Inc.
Phone (503) 620-3001
Fax (503) 620-6754
www.wavemetrics.com

DAQmx Trigger

I have two questions for the VI in attachment. I hope someone can help me :-)
1° The trigger does not work properly: measurements should start whenever the given value ( "Level" * hammer sensitivity) is reached on channel 0. In fact, if I make the value almost 0, it still doesn't work.
2° The charts should have a "memory" of 6 seconds: ( 10kHz rate at 10k samples per second and chart memory is set to 60k ).
After plotting those 6 seconds the program should stop ( therefore I used a for-loop, but I'm not too sure what number I have to attach to 'N').
Any suggestions?
Thank you in advance.
Dries
Attachments:
Daqmx_trigger.vi ‏40 KB

Thank you for your reply.
I don't know property nodes very well, but I already read something about wiring an empty array to the History Data property. The problem which occurs here is the following: if I create an empty array and I want to wire it to the History Data property of that Chart, the following error shows up:
Array element conflict:
The type of the source is 1D Array of Double, the type of the sink is 1D array of waveform.
I've tried to change the 'represetation' of the array, but the '1D array of waveform' type is not shown in the list.
About the reference trigger:
If I change the Trigger to a Reference Trigger, set the pretriggered samples to 1000 and run the VI, I get the following error:
Possible reason(s):
Measurements: Attempted to read a sample beyond the final sample acquired. The acquisition has stopped, therefore the sample specified by the combination of position and offset will never be available.
Specify a position and offset which selects a sample up to, but not beyond, the final sample acquired. The final sample acquired can be determined by querying the total samples acquired after an acquisition has stopped.
Attempted to Read Sample: 22362
Property: RelativeTo
Corresponding Value: Current Read Position
Property: Offset
Corresponding Value:
Task Name: _unnamedTask<8>
Now if I take a look at the Labview Help for Reference Analog Edge Triggering, I read the following:
"When you use a Reference Trigger, the default for the read RelativeTo property is First Pretrigger Sample with a read Offset of 0."
Does this mean that I have to use the DAQmx Read Property Node? If so, could you explain me how I have to use it?
Many thanks in advance,
Best regards,
Dries

DAQmx trigger: start digital edge

Buongiorno a tutti.
Mi trovo a lavorare su un VI creato in precedenza da altri colleghi, quindi sto cercando di migliorarne alcuni aspetti.
Lo strumento si occupa dell'acquisizione di segnali di temperatura e pressione da svariati sensori. I colleghi hanno inserito una fonte di trigger esterna attraverso un generatore di funzione (tektronix AFG3021C). In allegato una immagine della sequenza precente al ciclo while di acquisizione ed elaborazione dei segnali.
La mia domanda è questa: "è possibile ovviare all'utilizzo del generatore esterno di funzione?"
Grazie
Luca
Allegati:
acquisizione.jpg ‏155 KB

Ciao Luca,
strano che non ti compare niente, prova a cancellare l'intera funzione e richerla, dovrebbe almeno apparirti i vari PFI della scheda DAQ che hai collegato al PC... Sei sicuro di aver collegato qualcosa?
In ogni caso ***** vuoi come trigger una forma d'onda generate internamente, quello è un trigger software, prova a guardare questo esempo:
https://decibel.ni.com/content/docs/DOC-35941
Buon lavoro e buona giornata,
Valerio

How to sync CAN (traditional) and DAQmx input on PXI?

At the moment I am reading analogue samples and counter values on my PXI system. The counter value is incremented by an external pulse (i. e. current time). Because the pulse is the actual time, the AI sampling has to start in sync with the first incoming flank. This sync'ing is done via the DAQmx trigger VI which is set to "start at flank" (see picture). Because I am recording the counter values, too, I can always determine the time for each AI sample.
Is it possible to start AI and CAN signal sampling in sync with the first incoming pulse flank? As before, I want to store the counter values as well, so that I have time information for each sample. Is this sync'ing solvable with VIs or do I have to use a different CAN card with an external trigger input?
The CAN card is of type 8464 XS.

Hello,
please see the links below.
http://digital.ni.com/public.nsf/allkb/95EB3CB8E92D30FB86256F2C00672C44?OpenDocument
http://zone.ni.com/devzone/cda/tut/p/id/4204
Regards
Rüdiger

Error in reading voltage using DAQmx with PXI-6259

Hi,
We are trying to acquire analogue voltage from 5 channels using PXI-6259. We trigger the data sampling with clk 0 (i.e. using PFI 12).
The problem we had is:
1)When we tried to get voltage from 5 channels, we get 2 data at the same after twice the period. For example, If we set the
sampling rate to be of period 1 second, we get 1 signal at 2 second and around (2+t), where t is a random time less than the execution period of the loop.
Then the next cycles would be 4 second and (4+t).
2) This timing problem did not occur if we only acquire voltage from 2 or less channels.
3) We tried to run exactly the same program with NI USB-6210 and everything worked just fine.
4) We replaced the DAQmx read with DAQ assistant and still encountered the same problem.
Attached is the a simple program that showed the error. Is this possibly a bug in PXI or DAQmx?
Please help us
Arul (CLAD)
Attachments:
test rig.vi ‏74 KB

Good afternoon Nitin,
Thanks for contacting National Instruments with your issue, we'll try our best to resolve it for you as quickly and efficiently as possible.
As the error message stated:
"Analog input virtual channels cannot be created out of order with respect to their physical channel numbers for the type of analog device you are using. For example, a virtual channel using physical channel ai0 must be created before a virtual channel with physical channel ai1."
If you need to randomly switch which channels you want to either control IEPE excitation or coupling on, a better approach rather than having all of these channels in one task as you've done in your attached VI, is to parse your program down to multiple tasks that can run simultaneously.
I have attached a screenshot of this approach, which hopefully is not a compromise to your application.
Best of luck with your project.
Sincerely,
Minh Tran
Applications Engineering
National Instruments
Attachments:
ParallelTasks.JPG ‏52 KB

Route front trigger of PXIe 2593 to backplane for use with PXIe 5251

I have a PXIe 1062Q chassis with a number of PXIe 2593 Mux's which are connected to the two inputs channels of a PXIe 5251 Digitizer. What I want to do is to use the trigger on the front of the Mux to close the appropriate switches on the muz and to trigger the start of capture on the Digitizer, is there anyway to do this?
If not is there another way to do what i want?

Hi WayneR1,
Thank you for your question!
In order to route different signals (like triggers) on the PXIe backplane "DAQmx Connect Terminals"
VI should be used:
The source and destination terminals can be on different devices as long as a connecting public bus,
such as RTSI or the PXI backplane, connects the devices.
More detailed information can be found here: http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxconnectterminals/
Please make sure that you disconnect those routes after running your code.
Once routes has been connected, they will stay connected until you restart the PXIe controller
or use "DAQmx Disconnect Terminals" VI:
More information about "DAQmx Disconnect Terminals" VI: http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxdisconnectterminals/
I hope that you will find this information useful!
Kind Regards,
Max
Applications Engineer
National Instruments

PXIe-4499 DAQmx Trigger

Similar Messages

Maybe you are looking for