Digital triggering

By using pulse train during raiging edge, by digital triggering i have to write to digital port and during lowering edge, by analog triggering i have to aquire the data. how i can achieve with the PCi6036E and DIO-31HS?

Greetings,
I am not sure that I totally understand your application. Do you want to output a digital pattern with your 32HS on the rising-edge of a digital trigger and then acquire data with your 6036E on the falling edge of that same trigger?
Let me know if this is correct or not.
Spencer S.

Similar Messages

Two digital triggers

Hi!,
I´m in need for a little help. My problem is that I´dont know is it possible to use two digital triggers simultaneusly in 6225-daq. I try to do two same tests at same time. PFI4 line should be as a trigger for a line ai20 and PFI5 should be as a trigger for a line ai52. PFI4 and PFI5 lines get rising edges almost simultaneosly but, you can´t be sure which one happens first.
Program should be able to tell if PFI4 and/or PFI5 lines get rising edge at all. If example PFI4 line gets rising edge and PFI5 line doesn´t,program needs to acquire data from ai20 when PFI4 rises. if PFI5 line doesn´t rise in 0,5 s program should not acquire data from ai52 and it should give for example boolean value or something so you can write to file that test to this other device failed.
I can use digital triggers and all is just fine when I get rising edges to trigger lines but when not, program falls.
Attachments:
sama trig linja eri measure linjat 1_11_2005.vi ‏110 KB

Hi Jetfire,
do you know the difference between BMP and JPG?
Size! (And that's the reason BMPs are banned in this forum.)
Just renaming a file doesn't change the dataformat. Please attach real JPGs (or even better PNGs) next time!
Jetfire created a related thread, now with a VI instead of a picture...
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Can I use the 2 digital triggers on the PCI-6023E to trigger 2 seperate Analog inputs on the same board?

I want to monitor 2 analog DC signals (single point measurements, not a waveform) and I want to use the digital triggers to start the acquisition, 1 trigger for 1 AI. the measurements need to be made at 1Hz, maybe slower. Is this possible with the PCI-6023E?
If not what hardware should I be looking at? I have a total of 6 triggers and 6 AI.

Dimentia,
I would need confirmation on what you want to do:
1) I want to monitor 2 analog DC signals
This means that you will have one Analog Input operation monitoring two channels. Please confirm.
2) single point measurements, not a waveform
Ok, no buffers.
3) I want to use the digital triggers to start the acquisition, 1 trigger for 1 AI
This would mean that a single digital pulse or edge on a single line would start your 2-channel analog input operation. Please confirm.
4) the measurements need to be made at 1Hz, maybe slower.
Hardware-timed or software-timed? 1 Hz could be easily implemented with software timing. But the triggering could force you to use hardware timing. It will not be a problem but it would be good to know.
5) Is
this possible with the PCI-6023E?
Everything I mention above is possible with the PCI-6023E.
6) I have a total of 6 triggers and 6 AI.
This last phrase is what really confuses me and seems to contradict the previous sentences. Does this mean that you will want to perform 6 independent Analog Input operations, with its own triggers (one each)? Will every Analog Input operation have 2 channels?
I'll clarify why this is important:
- Each Analog Input operation can only have one hardware digital start trigger assigned to it.
- Only one Analog Input operation (multiple channels allowed) can be performed per board at any time.
Since the rates are so slow I would recommend that you perform sample all channels within a continuous acquisition and then discard the data that does not meet a certain condition. You could sample the triggers as well and discard those channels for which the trigger has not been received.
These are just some ideas based on my assumptions on the
problem. Assumptions are never a good thing so please confirm on the point s above and we'll try to help.
Thanks
Alejandro Asenjo
Applications Engineering
National Instruments

DAQPAD 6020e misses digital triggers during analog input (AI)

I am using a 6020E BNC DAQPAD to acquire two seperate 12kHz analog signals from a sonar through ACH0 and ACH1. The sonar generates a digital start trigger at the start of each ping to notify the DAQ that new data is to follow and i am using this to trigger my application through PFL0/ TRIG 1. Typical trigger repetition rate required/generated by the sonar is 20-30Hz but is selectable. My problem is that the board/software misses complete analog input data pings when the digital trigger repetition rate goes above 2-3HZ (ie I only receive 10% of the pings I desire). Analog sampling rate is 45kHz and I am acquiring 1-2kSamples per triggered acquisition. The problem happens using a Labview application based o
n a modified version of the shipped "Acquire N - Multi Digital Trig.vi" (and original). Any suggestions welcomed.

Hi,
I believe that the problem you are having is due to using the pause function to pause the acquisition before the next trigger and the fact that DAQpads do not have a DMA transfer mechanism. The default setting is to create an interrupt when the onboard FIFO buffer is half full. So when the pause trigger occurs there will always be data left on the FIFO, up to a half buffer of data.
To work round this problem you can use an external stop trigger instead of the pause.
Or it is possible to change the data transfer mechanism to cause an interrupt on every sample acquired instead of every half FIFO buffer. This will send every sample acquired by the DAQ board to the computer. The drawback is this method is very processor intensive and significantly slows
down data acquisition rates. As you are approaching the sampling limit of the card (100Ks/s or 50Ks/s for 2 channels) you may find that you will get buffer overflow.
To change the interrupt setting use the "Set DAQ Device Information.vi", which is located on the Functions Palette » Data Acquisition » Calibration and Configuration. See the LabVIEW help for information on using this VI.
Kind Regards
Tristan J
Applications Engineer
National Instruments

I want to acheive digitally triggered data acquisition and using AIO lines for triggering connecting to PFI lines but no response.

How to acheive digital data acquisitions using AO signals as trigger signal.

Greetings,
I am not sure that I have a clear understanding of your question. It appears that you want to perform a triggered acquisition. You mentioned both analog input (AI) and analog output (AO). Which type of operation are you performing? Are you using digital or analog triggering? Also, it would be helpful if you could mention what hardware and software you are using.
Spencer S.

Determine when Counter Pulse Generation has been digitally triggered to start

A counter task has been configured for continuous pulse generation with a digital edge start. How in LabVIEW can I determine when an external digital trigger has been received and the counter started ? It seems that a timed loop with DAQmx Create Timing Source wired to its source could be made to work but I cannot figure out how or the most appropriate instance to use. I would simply stop the timed loop once the counter start had been detected.
Steve

Querying the output state and looking for a change would probably work for many typical square-like pulsetrains. If you have an extreme duty cycle like 1% or something though, your queries are likely to keep finding the counter in the same output state long after pulses have started.
Some other ideas of a similar nature may work better, though I'm not near a LV machine to test them. I can vouch for idea #1 from past usage though.
1. Query the counter's 'count' property and look for a change. You're pretty unlikely to query the same count value several times in a row during pulse generation.
2. You could try querying the DAQmx property for "TotalSamplesGenerated" and look for a non-zero value. I'm not sure if this gets updated for counter outputs though.
3. Counters also have a property called "TC reached?" where TC means terminal count. When you query and get a True, It automatically resets itself back to False until reaching TC again. Again, while I know this works for counter input tasks, I'm not sure if it gets updated for counter outputs.
-Kevin P.

Digital triggering for analog acquisition on PCI-6024

I would like to initiate an analog input scan when a digital line goes low using a PCI-6024 board. I connected the digital line to TRIG, and the analog line to AIN0. I tried using "Acquire N - Multi-Digital Trig.vi"...it almost works. It acquires a scan, but it may (randomly) start at either the rising or falling edge of the trigger, regardless of the rising/falling trigger edge setting. How do I get it to only acquire data on a falling edge?

Dear Dave -- If you set up your task using MAX, you can specify whether you need to start acquiring at the rising or the falling edge. Using this task in your experiment should effectively take care of the issue.
You can do the same from LabVIEW as well using the DAQmx Trigger VI and set the acquisition to begin at the rising or falling edge as you may choose it to be.
HOpe this helps = VNIU

Digital Triggering With Pretrigger Samples

I am unable to trigger the PCI-6115 using the Digital Trigger A when the number of Pretrigger samples is greater then 0. Everytime I run the VI the acquisition times out. When I set the number of Pretrigger samples equal to 0 the VI works fine. I need to acquire pretrigger samples. What do I need to do to get the card to trigger properly?

EZimney,
Are you currently using the onboard memory of the PCI-6115? Currently, pretriggering is not supported in this mode. Please see the following Knowledge Base article for more information.
How Do I Use the NI 6115 and NI 6120 Onboard Memory to Store Acquisition Data for Later Retrieval?
http://digital.ni.com/public.nsf/websearch/9C419710B6071A6D86256BD600624B83?OpenDocument
Regards,
Justin Britten
Applications Engineer
National Instruments

Synchronize 2 USB-DAQ devices, Analog IN, Frequency IN, Digitally triggered

Hello,
I want to perform the following measurement on two USB-6211 devices, LV 2012:
I need to
1) read (cont.) all 16 analog input channels of Dev1
2) read( cont.) 2 analog input channels of Dev2
3) perform a frequency measurement with Dev2
4) synchronize 1-3
5) start the Measurements with a trigger (light barrier)
1) and 2) are not the problem. Also synchronizing them is fine. But I am not sure if my attempt to synchronize all this with the freq measurement, as this is done over a certain period of time. So, as I understand, when I select the method "high frequency with 2 counters" I can specify the measuring time. So I think I need to tell labview somehow which point of time of this span shall be synchronized with the analog input.
I attached a first try and am thankful for any hints.
Thanks, Jack
Attachments:
test.vi ‏42 KB

The basic problem here is conceptual. What does it mean to "synchronize" a time domain measurement with a frequency domain measurement? You can certainly can (and should) identify the set of time domain measurements that went into the calculation of the frequency measurement, but that's about the thinnest you will be able to slice this bologna.
Having said that, I can't look at your code right now but I assume you are reading data in blocks from the DAQ. You could perform the measurement for each block you read. That would naturally associate the measurement with the data it was based on.
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
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Digital triggered, synchronized AO, AI

How do I get the AO and AI to share a clock using DAQmx? I have a RTSI cable, but am not sure how to configure the devices. The output device will be stepping through an array of analog voltages at a predetermined rate. The input device will be scanning all channels for exactly the same duration of time that it takes to step through the voltage array.

While the example included by Sal will work, you can leverage the automatic routing feature of NI-DAQmx to avoid having to specify a RTSI line at all.
For example, in Sal's example, you can specify "Dev1/ai/SampleClock" as the source input to the "DAQmx Timing (Sample Clock)" VI rather than "Dev1/RTSI0." In addition, you can now remove the "DAQmx Export Signal (Most Signals) VI from the diagram. NI-DAQmx will automatically route the analog input sample clock signal to the analog output subsection of the device. I believe a RTSI line will still be used, but you don't need to explicitly specify a free one.
However, if you are using the same device for analog input and analog output, the "Multi-Function-Synch AI-AO-Ext Dig Trigger" example VI provides a more flexible solution. In this example, only the analog input start trigger is routed to the analog output start trigger (which I believe consumes a RTSI line). The analog input sample clock doesn't need to be routed to the analog output subsection since both sample clocks are derived from a shared master timebase. This example also allows the analog input and analog output operations to run at different rates.
If you are using two different devices for analog input and analog output, you need to route the master timebase as well as the analog input start trigger. The "Multi-Device Synch - Shared Timebase & ext Dig Trigger" example VI illustrates how to route the master timebase from one device to another. In this example, NI-DAQmx will automatically choose a RTSI line; you don't need to specify one. (Note that while this example is for synchronizing two devices performing analog input operations, it is still a good example of how to share the master timebase).
geoff
Geoffrey Schmit
Fermi National Accelerator Laborary

Analog,digital and pfi triggering of PXI 6133 card

Hello,
i am using PXI-6133 card. i observed that there are three type of triggering options(i.e., analog, digital and PFI) available on each card. i want to know the difference? and also best one.
regards
chandu

Hi chandu,
Analog triggering is based on the value of an analog
signal. For example you can trigger when your analog signal goes above or below
a specified value. Digital triggering happens on a rising or falling edge of a
digital signal. For either type of triggering you must have a trigger source
that is the signal you are triggering on. For digital triggering on your card this
can be any PFI line. For analog tirggering it can be any analog input channel.
A detailed explanation of the triggering capabilities of your PXI-6133 can be
found in the S-Series User Manual. Triggering is discussed in Chapter 13. Also
a more great summary of triggering in general can be found in the Developer
Zone article, Tips and Techniques in Data
Acquisition Triggering - NI-DAQmx. What triggering is better depends on your
application and which one is more suited to your trigger signal. If you have a
digital trigger source then digital triggering will work great. If your trigger
source is an analog signal than you will probably need to use analog triggering.
Let me know if you have any questions and have a great weekend.
Thanks,
Nathan
National Instruments
Digital Hardware Engineer

How to use digital trigger with analog I/O

How do I program analog input and/or analog output to start on a digital trigger (PFI pin) on PCI-4451/4551.
I have tried out various configuration and succeeded in starting analog input, simultanuous input and output triggered by the the anlaog input signal. I have also succeded i triggering 4551 from the dedicated EXTTRIG pin.
The problem is to trigger on a selectable PFI pin. I find the help for "AI Trigger Config" and "AO Trigger and Gat Config" misleading - some unsupported features seem to work while selecting PFI pin as source make the PC restart immediately.
I have not been able to find any LabVIEW example that shows how to use PFI pin as trigger input.
Using LabVIEW 7.1, NI-DAQ 7.3 on Windows 2000.
Kind regards / Med venlig hilsen
Torben

Hello
The PCI-4451 does not have any PFI lines. If you look at the user manual in the link beneath you will be able to confirm this by looking at the connector signal discriptions. The same is valid for the PCI-4451
http://digital.ni.com/manuals.nsf/websearch/6A32358C53BB15F086256660007392DC?OpenDocument&node=132090_US
The two ways of triggering that you have succeded are the analog triggering and digital triggering that you can peform with the PCI-4451.
Regards
Mohadjer

How can I output a digital value (0 or 1) directly with a VI on the RTSI-bus?

The Device is a PCI-MIO-16XE10.
Thanks.

The RTSI bus is designed for sharing timing and control signals between boards. By timing and control we mean clock signals, digital triggers, etc. RTSI is not meant to pass I/O signals, even digital I/O signals. Thus, it is not possible to connect one of the digital I/O lines on your board to a RTSI line. A way to accomplish what you would like to do might be to toggle GPCTR0's Output and connect that signal to the RTSI bus. You would do this by configuring the counter to perform event counting and counting down from a specified number of pulses on the source pin and configuring the counter's output to toggle on terminal count. You could also configure the counter to perform pulse train generation or single pulse generation. To connect the output to the RTSI bus, yo
u will need to call the Route Signal VI from the DAQ Calibration & Configuration Function Pallette with Signal Name set to RTSIn and Signal Source set to GPCTR0 Output.
Regards,
Erin

Sound triggering on PCI-6023E

I am using a PCI-6023E card. I wish to use a sound signal to trigger the data acquisition. Since it has only external digital triggering, my best guess is to run a sub-VI that reads the microphone channel and then sends a digital output to the external trigger channel. Any better suggestions? Any comments on the brain-drain effects of this on my buffered data (while waiting for the trigger event)?
thanks

Hello,
Depending on the level of the sound signal that you will be receiving, doing an analog input and then in software determining if the level if your signal is high enough would be your best option if the sound signal you are receiving is not a TTL signal. But, as far as then generating a digital output that then triggers the analog input externally doesn't seem to be needed. If you are producing a software signal to trigger something anyway, you may as well just start the analog acquisition in software once your subvi has determined it is time instead of generating a digital output that then hardware triggers the acquisition.
Regards,
Steven B.
National Instruments

How to use analog Triggering and External clock scan

Hi, there. I want to measure the engine cylinder pressure with an PXI6070-E card and BEI encoder. I have tried using Cont Acq&Graph ExtScanClk D-Trig.vi and Cont Acq&Graph ExtScanClk Soft A-Trig.vi , but they don't work. What I did was to connect a 50HZ pulse to PFI0 (analog triggering, I changed the code from digital triggering to analog triggering), and a 100K pulse to PFI7 (startscan), and an 50 HZ analog signal to ACH0. But the code always says: timeout. If I use internal clock, it works fine. Could you please give me some help? THANKS A LOT!

Hey Wyuan,
I tested the Cont Acq&Graph ExtScanClk Soft A-Trig.vi and it worked fine. However, the Cont Acq&Graph ExtScanClk D-Trig.vi has a small error in its logic that will prevent the data from ever being displayed to the graph. In order to run the examples you need to connect a trigger to pin 11 and a scan clock to pin 38. A 10kHz square wave would be fine for the clock signal and just a single pulse would work for the digital trigger.
One additional think to keep in mind is the grounding. You might need to connect you ground from your signals to a DGND pin. I am including the two programs that I used for the test.
I hope this helps,
Joshua
Attachments:
Cont_Acq&Graph_ExtScanClk_D-Trig.vi ‏121 KB
Cont_Acq&Graph_ExtScanClk_Soft_A-Trig.vi ‏153 KB

Digital triggering

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