Analog Trigger with PXI-6229

I have an application using a PXI-1010 chassis, PXI-6229 DAQ, communicating with MXI-4 to the host computer.
For task triggering, the only direct option I'm finding is the digital trigger. However, I need to trigger on a low-lever analog signal (180mv). Can this be accomplished indirectly and start the task with a minor delay? If I can trigger the signal on the positive slope, I could have potentially a 1ms delay to begin the task and not affect my data.

Hello Russ,
The M Series 6229 should be able to support hardware analog triggering. Take a look at the following example to see how to accomplish this in LabVIEW.
http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_answer=&p_guid=DC9C549F7FDC1973E034080020E74861&p_node=DZ52000&p_rank=&p_source=External&p_submitted=N
If this doesn't work out for you and you don't mind having a delay between the low-level analog signal and the start of the task, you could always use a software analog trigger. Examples of this can be found in the LabVIEW NI Example Finder.
Take care,
E.Lee
Eric
DE For Life!

Similar Messages

Is it possible to start a PCI4472 and a PCI-MIO-16E-1 simultaneously using an analog trigger (with pre-trigger)?

I would like to start several PCI 4472 and a PCI-MIO-16E-1 simultaneously. All boards are connected via a RTSI cable.
My program works fine if I use software trigger, or an analog trigger from a PCI4472 channel. However, the analog trigger works only when I set pre-trigger (or pre-scan) to 0.
Is it possible to start a PCI4472 and a PCI-MIO-16E-1 simultaneously using an analog trigger (with pre-trigger)?
Thanks.
Ian Ren

Hi, Bill
I think it is possible to set more than 38 pre-trigger scans on a single 4472 card. I've done this before. You can verify this by running the Labview example "Acquire N - Multi-Analog Hardware Trig.vi" which comes with LabView.
What I try to do but without success/luck so far is to start data acquisitions of several 4472 cards and a PCI-MIO-16E-1 card using an anlog trigger (with pre-trigger).
Thanks for your help.
Ian

Monitor multiple channels for analog trigger with DAQmx drivers

Hello! I would like to start a data acquisition of multiple analog channels (16) from an analog trigger. I would like trigger to monitor four of the (same) channels, and trigger when any one of them reaches a certain voltage. I found an example that would work with the Traditional DAQ drivers (using occurances), but can't figure out how to do something similar in DAQmx.
Time is also an issue, as I would like to collect the first 80 milliseconds of data after the trigger (at a rate of 500,000 Hz).
I'm using LabView 7.0 and collecting data off of two PXI-6133 cards.
Thanks for your help!

Hi Denise-
After some research, I have found that it is not possible to use the functionality of DAQ Occurrences in DAQmx. Ironically, the reason that this functionality is available in Traditional and not DAQmx is due to the exploitation of an inherent limitation of Traditional that was upgraded in DAQmx. The multi-thread capability of DAQmx is a major advantage for most applications, but in this case it prevents the use of occurrences as they existed in Traditional DAQ.
In short, this means that you can't directly use this functionality in DAQmx. You can however emulate this functionality with minimal software analysis of the incoming signal. I have attached a modified example VI that logs data to a chart only when the analog level of one of the channels being measured has exceeded a user-defined reference value. Basically, the task is running continuously in the background but the data is not actually logged until the signal is above a predetermined "trigger" level.
Please let me know if the attached example is helpful for your application. You will see the input channels listed in the format "DevX/ai0:y" where X is the device number and y is the highest channel number of interest.
Regards,
Tom W
National Instruments
Attachments:
Cont Acq&Graph Voltage-Int Clk Analog SW Trigger.vi ‏83 KB

Analog trigger with NI9205 PFI0

I have a problem to trigger an analog acquire with NI9205 (C module in Compact DAQ)
i use the PFI0 line, but the acquire don't start when i send a trigger gignal (5 to 0V)
the error:
could you help me?
Thanks a lot!

You set your task up to run at a rate of 2400 samples per second, and request 64 samples to be read. This means that it will take at least 37.5ms to take the data.
Your DAQmx Read function has a timeout of 10ms set. This means that the read will always timeout before the required samples are read as the error is indicating.
For this configuration you should not need to wire the timeout setting of the DAQmx read at all, I recommend removing that input!
Craig H. | CLA | Systems Engineer | National Instruments

How to do an analog trigger with bipolar levels of detection and start acquisition with pre-trig samples

hello,
I use PXI 4472 with accelerometers. I want to trig as soon as the acceleration is out of the window +/-50g and recover the previous samples before the trig. Is it possible to do it?
I try the daq-mx functions trig on analog windows and a number of pretrig samples but without success. My first sample detected is always over 50g, it seems that the number of pretrig samples has not recognized. Anyone to help me?
Thank you.

Hi Chouca,
It should be possible to do what you are trying to do:
type of trigger: analog window triggering (acquire data when the signal leaves the window)
Action caused by trigger: reference trigger
I will try and get a 4472 to check that by myself.
Maybe it would be easier to check the behaviour of the system with a precise voltage generator instead of the accelerometers.
Best regards,
Thomas B. | CLAD
National Instruments France
#adMrkt{text-align: center;font-size:11px; font-weight: bold;} #adMrkt a {text-decoration: none;} #adMrkt a:hover{font-size: 9px;} #adMrkt a span{display: none;} #adMrkt a:hover span{display: block;}
>> Inscrivez-vous gratuitement aux Journées Techniques : de l'acquisition de données au contrôle/com...

Problems with setting up analog trigger with NI 6289 with VB6 [with error 200265]

I have been trying to synchronize an analog input read with an analog signal generated by the Multifunction DAQ (NI 6289). Basically, the voltage AO signal is fed into a laser and the resulting intensity profile is read into a photodiode, which generates an AI signal read back into the DAQ. The two channels have the sampling rate and buffer size / number of samples.
However, triggering has presented with some problems; the manuals were not very clear on the subject of connecting channels, and no sample programs exist so far that demonstrate this on VB6.
What I have tried is physically connecting /Dev2/ao0 with /Dev2/APFI0, ( Dev2/ai0 is connected separately). Below is a little snippet of code:
'initialization goes here
    DAQmxErrChk DAQmxCfgAnlgEdgeStartTrig(inputHandle, "Dev2/APFI0", DAQmx_Val_Slope1_RisingSlope, txtOffset.Text)
    DAQmxErrChk (DAQmxReadAnalogF64(inputHandle, numSampsPerChannel, 10#, DAQmx_Val_GroupByScanNumber, dataBuffer(0), numSampsPerChannel, sampsPerChanREAD, ByVal 0))
    DAQmxErrChk DAQmxWriteAnalogF64(outputHandle, numSampsPerChannel, False, 10#, DAQmx_Val_GroupByScanNumber, optData(0), sampsPerChanWritten, ByVal 0&)
    DAQmxErrChk DAQmxStartTask(outputHandle)
I received the following error, -200265, "attempting to use an invalid analog input trigger", at the line ReadAnalogF64.
Attached is the code I used for the triggering event. Any help would be greatly appreciated.
Attachments:
Trigger method.txt ‏2 KB

Refer to this thread please.
Message Edited by Chris W. on 04-10-2009 10:32 AM

Analog trigger with 6071e in C

I'm using the NI6071e MIO board and what I need is to perform SCAN_Op continously on 4 AIs. When a trigger of 1.1V reached in AI2 - stop trigger, I need 300 samples pretriggered plus 200 samples of poasttrigger data (total of (300+200)*4 = 2000 samples. I'm writing code in C, using the Microsoft VisualStudio and the traditional NI-DAQ library. Does anyone can explain on how I should perform it? Does anyone have similar code?
I've been directed to a LAB View example that unfortunatly I can't read.
Thanks,
Nir.

Hello,
I'll try to offer some tips. It looks like you are trying to set up two different triggers for an analog input. This can not be done. Some different options for you are to use pause triggering, reference triggering, or some sort of software triggering. Pause triggering will allow you to collect data when the voltage is above (or below) some trigger value. When the voltage drops below (or above) the trigger value it will no longer acquire data. Another option is using a reference trigger. You can set up a reference trigger to acquire a predetermined number of data points before and after a trigger. Another option might be to use your analog signal as a start trigger for a continuous acquisition. Then, in software, monitor the data being acquired from the trigger channel. When the trigger channel acquires some data that is below your trigger level, stop the acquisition in software (after you have acquired all of your post-trigger data points). I hope this information helps!
-Alan A.

Analog Trigger unavialable in PXIe-4353

Hello,
I'd be grateful for some help with my case. I'm building a VI for acquisition of multiple signals from thermocouples. My hardware is NI PXIe-1073 chassis with PXIe-4353 module to read the signals.
The problem is that I want to use an Analog Edge trigger for the start of the measurement but it is unavialable to choose in the DAQ Assistant properties window (I have only None and Digital Edge to choose form). I also tried to do the same with DAQmx functions but I got the Error which says that I can only choose Digital Edge Trigger or None.
The hardware (PXIe-4353) does seem to support Analog Triggering: http://zone.ni.com/reference/en-XX/help/370471W-01/cdaqmxsupp/pxie-4353/ or am I mistaken ?
Also I want to note that I currently use hardware simulation and not the actual hardware - can this be the reason?
My VI and SubVI are attached to this post. I'm new to Labview so I may have made some silly mistake. Please let me know then
Attachments:
poczatek.vi ‏124 KB
poczatek.vi ‏124 KB
DAqass.vi ‏70 KB

Dear pancarlos,
Unfortunately, the hardware does not support analog triggering, as stated in this thread. If that is necessary in your application, you might want to consider adding another PXI card to the system that does trigger on analog input, and use the trigger lines to start your PXIe-4353.
Regards:
Andrew Valko
National Instruments Hungary

High speed sampling with analog trigger

I am a new user of DAQ card and I need to sample the analog signal with a high speed.
I will use a sinusoidal-like wave to trigger the sampling and set a voltage around the peak of trigger wave with rising slope. When the voltage arrived, I only sample one point from CH0 or CH1. The frequency of the trigger wave is about 5MHz and I heard the LabView only works at KHz level. Is it possible to use LABView to realize my application?
If it's possible, would you mind telling me how to realize? Or if it's not possible, would you mind telling me what to do? My DAQ card is PXI-5112.
Thank you very much!!!

Hello amo71993,
I guess in this case the solution is creating the little app programatically, save it as a VI and the use it as a function (subVI). Nevertheless I will be researching to see if there is another option and I will post it here.
Regards.

Anyone have an example of a PCI-6250 Digital and Analog Aquistion with Analog Post-Trigger?

Hey All,
We're trying to set up a post trigger data capture of parallel absolute strobed Gurley 17-bit encoder data (ignoring MSB for 16-bit aquisition) with an analog signal that is the output of a torque load cell. The trick is to use the analog signal level as a post-trigger to stop the data aquisition.
1) can the analog signal be recorded and used as the trigger?
2) does anyone have an example using the PCI-6250 (or 6251)
Thanks in advance for your help,
-Drewksi

Hi Drewski,
You can use the APFI0 line as an analog trigger for your signal. However, in this case you need to connect your analog signal to both the analog channel you want to acquire at and the APFI0 line.
Assuming you are using LabVIEW,you can check the "Acq&Graph Voltage-Ext Clk-Analog reference.vi" example. This examples uses an external clock but it works also with the internal clock. All you have to do to change the control to onboard clock.
You can find this example in LabVIEW Help >> Find Examples >> Hardware Input and Output >> DAQmx >> Analog Measurement >> Voltage
Best Regards,
Faris
Bueller

Hi, iam facing proble in synchronizing 4 ni 4472 cards input with pxi -6052e analog output. please help me out to sort out this problem

hi, iam facing problem in synchronizing 4 ni 4472 cards input with pxi -6052e analog output. please help me out to sort out this problem

Hi achyuth,
Thank you for posting on the National Instruments forum.
I am not sure what you are trying to do. Are you trying to input and output at the
same time? Are you just trying to
synchronize all of your inputs? Do you
want them to run off the same clock? If
you could, give me some more information so I can understand your problem
better.
In the meantime, this might help you:
PXI Timing,
Triggering, and Synchronization Capabilities of E-Series Multifunction Data
Acquisition ...
PXI Timing and Synchronization
Thank You,
Nick F.
Applications Engineer

I use a PCI MIO 16E board with an analog trigger. So I wire chann

el 0 to the PFIO line, and I enter "PFI0"as the triggering channel on the front panel , I put a level,and I declare channel0 and 1. When I do a DAQ it seems that PFI0 detects the signal as I haven't a timeout, but it doesn't trigger off at the good level.

el 0 to the PFIO line, and I enter "PFI0"as the triggering channel on the front panel , I put a level,and I declare channel0 and 1. When I do a DAQ it seems that PFI0 detects the signal as I haven't a timeout, but it doesn't trigger off at the good level.I noticed you posted an earlier question that generated several responses about the valid sources of an analog trigger. Was there a reason you decided to use the PFI0 option over just telling LabVIEW to use Analog channel 0 as the trigger source? At what voltage level are you wanting to trigger?
Also, if you use the Analog Trigger examples in LabVIEW or the DAQ examples for your compiler, do you get better results?

60 HZ Hum on Analog Input PXI-6229

Ther is a 600mV common mode noise hum being introduced somewhere on the circuit below. It is causing the PXI-6229 to read inaacurate measurements. Is there a way to configure the device to reject common mode noise? Or any other suggestions?

Is the metal box connected to both the power system (safety) ground and the signal ground? This could be the source of the ground loop. Are the computer, PXI chasis, and the metal box power all connected to the same branch circuit and ground?
Try drawing a diagram showing every ground connection in the system. Do not just use a ground symbol but actaully make it a wiring diagram which shows where every wire, chassis, box, conduit, or anything else grounded is connected. This can sometimes be useful in discovering ground loops. I found one which included a wire attached to the mounting bolt for a toroidal transformer. It resulted in several amperes flowing through the housing of a very sensitive magnetic instrument!
As has been mentioned CMRR only applies to differential inputs. The circuit you posted is single ended so I think it is unlikely that a differential connection would help.
Lynn

Timebase synchronization issue with PXI 6713

As indicated in another post, I need to use a common timebase to all cards within my PXI chassis to synchronize my acquisition/generation DAQmx tasks.
I performed that successfully by setting timebases of all boards from the 20MHz timebase of a E-series DAQ board.
I have another system setup where I do not have E-series DAQ boards but only M-series. In this case, I tried to synchronize all the cards with the 10MhzRefClock of a PXI 6254 board. It seemed to work correctly, until I looked at the analog output signal of one PXI 6713 board.
This device has 8 analog outputs, I performed as for DAQ boards : I set its timebase to a 10Mhz clock. When I have at least two outputs with hardware timing I observe on scope really weird signal : nothing is visible when all outputs are left to zero volt, but when another voltage is set, the output toggles at very high frequency between 0V and the setting voltage. When two outputs are set to values different from zero, the output also toggles but between these two settings...
I thought it was a board failure, but I checked with another PXI 6713 and the behavior is the same.
When synchronizing with a 20MHz timebase, everything is fine, but 10MHz clearly shows this issue. I checked the 6713 documentation, and it seems possible to use a timebase different than 20MHz.
I attached a VI that illustrates the problem : I create a DAQmx task containing 2 AOs, where 10MHz timebase is taken from a M-series DAQ board. A hardware timed single point timing is configured and outputs are updated in a while loop. If you connect a scope to the first analog output, you will see the phenomenon.
Everyting is fine when you select a 20MHz clock as a timebase. 10MHz leads to this issue. I also tried to synchronize through PXI backplane clock (i.e. /6259_1/PXI_Clk10) but it leads to the same problem.
Please note that using the same 10MHz synchronization on DAQ cards (PXI 6040E, 6071E, 6254, 6259...) for AO works perfectly. I only encountered this problem with PXI 6713 board.
Message Edité par Inpriser le 08-18-2006 02:54 AM
Attachments:
Synchro 10 MHz PXI AO.vi ‏34 KB

Inpriser,
You wanted to use the PXI 10MHz clock to synchronize to 6713s using the PXI capabilities. I’m afraid that since the AO series doesn't have a PLL, you won't be able to use the PXI 10 clock.
I made a few search and found this:
“Neither the 6713 nor any of the AO series support PLL synchronization. However, the M-Series does, though in that case you are limited to a smaller number of analog outputs. Regardless, the best option is using an Arb or other card that can use the Star Trigger, or an m-series device with PLL synchronization capabilities.”
For more info’s about how to deal with PXI and PLL, please check this forum:
http://forums.ni.com/ni/board/message?board.id=170&message.id=11986&requireLogin=False
I’m sorry to disappoint you, hoping you’ll manage to deal with that,
Regards,
BRAUD Jean-Philippe
Field Sales Engineer - Nord et Centre France
LabVIEW Certified Developper

How to use an analog trigger to determine single sample acquisition rate

Hi all,
I have the NI PXIe 6124 on a NI PXIe 1062 Q controller.
I would like to use an analog signal to determine a single sample acquisition rate.
For example: if I enter a sine wave with an unknown frequency, I would like to acquire a single (1) sample across my 4 channels each time the sine wave value is zero.
Is this possible with my devices? And if so how do I do it?
Thanks,
Oren.

Hello Orensag
The different types of triggers supported can be found in the PXIe - 6124 Manual on pages 135-138. You should be able to set a very small window trigger with around 0 volts so that you trigger on both the rising and the falling edges of the sinewave as it crosses 0 volts.
Do you know the frequency of the input sinewave? This information would be very beneficial to know to set the correct rate for the DAQmx task.
What you really are looking for is change detection, which is an option in DAQmx Timing VI, but is only supported by certain cards. Again your sine wave would need to meet the same sample clock timing requirements in the 6124 Specifications.
Anthony F.
Product Marketing Engineer
National Instruments

Analog Trigger with PXI-6229

Similar Messages

Maybe you are looking for