Trigger-digital pattern

I would like to use "digital pattern" to control a/d acquisition. i.e. a start pulse on one line and a stop pulse on another. I am using a USB 6251. This menu item is grayed out. Does that mean SE does not support it or my USB device? Any work arounds?
Thanks
CHuck

Hi Chuck,
The USB 6251 and our other M series devices do not have the ability to trigger off a "digital pattern". Digital Pattern triggering is supported by some of our Digital I/O boards such as the PCI 6533 / 6534. Is there a reason you require two lines to start and stop the analog input acquisition? Can you just use one line with on and off states (high and low)? Also, is there an actual digital pattern you must recognize before turning "on" and "off" the analog input? I don't know of any way without some external hardware to accomplish a hardware timed digital pattern trigger. With more information on exactly what type of pattern you are trying to recognize there might be a workaround. You could accomplish software timed digital pattern triggering by just reading in the digital lines and turning on and off the analog input in software. However, if you're looking to use a hardware timed trigger to just turn your analog input on and off. I would recommend looking at using a counter to generate a continuous pulse train to be used as the sample clock of your analog input. This way you could use the "on" and "off" lines to toggle the gate or use one line to turn the gate on or off. This would turn the sample clock on and off and allow you to control when samples are taken. You would just need to set the source of your sample clock to be the output of the counter. I would take a look at the Gen Dig Pulse Train-Continuous.vi example (Help » Find Examples » Hardware Input and Output » DAQmx » Generating Digital Pulses) and see if it will allow you the control over the sample clock that you require.
Regards,
Paul C.

Similar Messages

Can I use differnet patterns for a "digital pattern match start trigger"

Hello,
Currently I would like use different patterns for a trigger the PCIe-6537 board to start capture data, for example, two patterns: 1101 and 1100 in digital IO lines line0:3, whenever one of this two pattern happens, start capture.
It seems like "digital pattern match" in DAQmx trigger can use one pattern only.
thanks!

Hi tt_ni,
Pattern I/O only allows the acquisition
based off of one pattern. This is a “limitation” of the hardware based on the
registers being set a certain way and monitoring a change from that. You could
add external circuitry to OR your patterns and based the pattern I/O off of the
output of that external circuitry. The other option is to look at an FPGA
option.
Mark E.
Precision DC Product Support Engineer
National Instruments
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What it the valid trigger delay value for "niScope Configure Trigger Digital.vi" ?

Hello:
I am using "niScope Configure Trigger Digital.vi" in LabView 5.1.1 for NI5911 scope card.
The trigger source is RFI1.
I am trying to specify the trigger delay, but it looks like the only accpted value is 0.0s.
For example: setting delay time to 1ms (1.0m) results in the error message stating that invalid value had been passed for trigger delay.
Thank you.
--daevper

The NI 5911 high speed digitizer does not support trigger delay; therefore its only valid input parameter for trigger delay is zero. The two high speed digitizers which do support trigger delay are the NI 5112 and the NI 5122.
There is a helpful listing in the NI High-Speed Digitizers Help which displays the features supported by each device (Start >> All Programs >> National Instruments >> NI-Scope >> Documentation >> NI High-Speed Digitizers Help >> Content tab >> Devices >> Features Supported by Device). If you did not install the documentation along with the driver, you can also download this support file here.
I hop
e this helps!
Regards,
Sonya Wornson
Applications Engineer
National Instruments

Use angular Encoder position to trigger Digital out

Hi,
I am a beginner labview user, I have access to three modules, two NI9201 and one NI9401.
I have an angular encoder that is used to measure the angular position of a motors crankshaft, what I'm trying to do is use the encoder to trigger a digital out (spark event in the engine) at a certain angular position. For example, I would like to trigger at top dead center (or 0 degrees on the encoder), then I want to be able to change this to +5 degrees on the encoder, etc.
So far I am able to read in the angular encoder when the motor is running, I am also able to output digital out signals although I can't find a way to link the two together.
If anyone has any idea how to do this, it would be greatly appreciated, I have attached my VI.
Thanks in advance,
Nick
Solved!
Go to Solution.
Attachments:
Encoder_Spark.vi ‏40 KB
Encoder_Spark.vi ‏40 KB

Hi Nick,
I hope the attached vi will get you on track. It's just a general concept.
The while loop will run until you hit the stop button.
   I take it you will need one spark per revoultion.
This VI is really just an If/Then
   If the encoder value is equal to (in this example ) zero,
   Then trigger the digital output.
I know I have a broken wire, but I didn't know how to get the angular position from you DAQmx.
Let me know if this help. (Also let me know if I'm off target)
Good luck,
Bill
Attachments:
Trigger spark concept.vi ‏9 KB

Getting error -200452 using DAQmx Base Trigger (Digital Edge).

I'm trying to set up AI and counter output, and I'm using digital output as trigger for to start AI and counter at the same time. I get error 200452 "Specified property is not supported by the devise..." not consistently, but around 5 runs out of 100. Below the error description, the error box shows "This error code is undefined. No one has provided a description for this code..." If I "Retain Wire Values" in Block Diagram, the error first appears after 'Start Digital Edge' block in top counter output line.
Using LabView 8.5 on MAC OS X and DAQmxBase 3.2
The MAC I have is not Intel base, so I can't upgrade LabView and DAQmxBase to latest version
Note: The file contains just a small portion of the program, but the rest of the program does not have any other DAQmxBase blocks accessing the channels used here in code attached.
Attachments:
Combined V 1.5.41_sm.vi ‏98 KB

Hi Azotov,
It looks like the DAQmx Base driver readme includes Mac OS X support for LabVIEW 8.5. Could you specify what hardware you are using?
I found one KnowledgeBase specifying that error code occurs when you try to use certain properties with certain devices. Of course, this would most likely occur every time you run the task, not 5% of the time.
Since I'm running Windows, it's a little difficult to see if you have DAQmx Base "Reset Device" functionality with that version of the driver. You might check if you can run that functionality before using your device, though.
National Instruments

Synchronise digital pattern output(6533) with a external signal

I use a PCI-DIO32HS and i want to synchronise an output pattern with an external signal(TTL;T=1.7ms).
ie :every time external signal become high(every 1.7ms)
my dio32HS output a define pattern on a line.
How can i do this?Thanks

Thanks for your answer but see attached file to see what i want to do.
I want to control delay between trigger(input signal T=1.7ms) and ouput and control the width of the ouput pulse
Best regards
Attachments:
signal.txt ‏1 KB

Trigger digital output at every 10 digital pulses

How can i generate an output pulse at every 10 input pulses comming from an encoder?
I need to trigger a sensor at every 10 encoder pulses to get data from the sensor.

Hello jyp777,
What you will need is a counter with an if statement that activates a digital output every 10 ticks. To do this, I would look at a LabVIEW example titled: Counter - Count Edges (Continuous Clock) that can be found under Help >> Find Examples... >> Hardware Input and Output >> DAQmx >> Counter Input in LabVIEW. Using this example VI, it should be a simple step to add a condition that triggers a digital output when the count reaches 10.
You can also use a Digital Output example if you need help in this area. These examples can be found by going to :
Help >> Find Examples... >> Hardware Input and Output >> DAQmx >>Digital Output. I would recommend "Digital - Continuous Output.vi".
Happy LabVIEW coding!
Thanks,
Collin D.
Applications Engineer
National Instruments

Re-start Digital Pattern Generation

Using the 6534:
If I start pattern generation with "Start" VI. Upon completion can I run start again to write out the remaining information in my buffer?

So after your first pattern generation is complete, you want to be able to write another block without reconfiguring?
Look at the "Buffered Pattern Output.VI" shipping example for reference. You will call DIO Write and then DIO Wait each time you want a new block transfered. (You will only have one DIO Start) You still have to wire the data you want transfered, but this way you could change the data if you wanted to. From your wording, I couln't tell if you are wanting new data written or different data written, but it should be the same. Finally, just call DIO Clear as you normally would.
I hope this helps!
Russell

NI DAQmx Digital Output Trigger To Start Analog Input Task

Hi everyone. I am using the NI DAQmx VIs to set a digital output line low (boolean '0'). I want to begin reading an Analog Input voltage (Start Analog Input Voltage reading task) right after the digital output line is set low. I am using the DAQmx Start Trigger (Digital Edge).vi to try and do this. I have the digital edge to trigger off a falling edge since the digital output line is being set low. I am using "do/SampleClock" as the source into the DAQmx Start Trigger (Digital Edge).vi.
I don't have the DAQ card (PXI 6229) since someone else is using it but I wanted to write up the SW so that when it becomes available I can have SW to try out.
I have attached the VI. Am I setting up this VI correctly?
Thanks!
Attachments:
Trigger AI Task Off DO Edge.vi ‏32 KB

I think you are going to have to wire that Digital Output to a PFI line on the card with the Analog Input(s). You then trigger on that PFI line.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

How can I use the hardware compare feature of the 6551 card to trigger scripts

I can dynamically and seamlessly generate different waveforms by triggering different scriptTriggers that drive one or more of the 4 PFI lines. However, I need to evaluate a channel at a specific location or locations set by a script marker in real-time and generate a different waveform stored in on-board memory based on the result of the evaluation. I have attempted to use the hardware compare feature without any success. I am trying to dynamically respond to an I2C device based on the ACKs or NACK response of the device under test. Can the 6551 card accomplish this? Has anyone successfully tested an I2C or SMBus communication stream with 6551 card?

Hello,
I can understand why hardware compare did not work out for you application. Hardware compare uses a signal that was generated to make a digital pattern and then waits a few clock cycles before acquiring the signal that needs to be compared to the digital pattern.
I would look into using a script trigger to evaluate the channel value, where the script structure controls when it is evaluated. Please note that script triggers will need to be cleared after they are detected for reasserting. Some script syntax actually clear the script trigger and then use a wait until script trigger structure. Please refer to the HS DIO Help for documentation on Common Scripting Use Cases.
Please provide us with further details about your application. The more information, the better! I was not too clear on what you where wanting to evaluate and where is it coming from.
I would also like to mention that National Instruments has a NI USB 8451 which is capable of I2C communication.
NI USB 8451
Samantha
National Instruments
Applications Engineer

Synchronizing analog and digital i/o

We're using LabView 6.0 and a PCI-MIO-16E-4 to run our electrophysiology experiments, and have a moderately tricky set of requirements.
What we have so far: four analog inputs and two analog outputs to monitor and control two recording electrodes. We need tight synchronization (within << 1 msec) between input and output so that we can properly correlate the timing of responses with the timing of stimuli during each presentation (which are no more than a few seconds long). We do this by using the Clock Config AIs to have our output side set the scan clock (via the AO update signal through PFI 5) and the input side use that scan clock. This all works and we're happy with it.
What we need: we'd like to independently control at least 6 (preferably more) stimulator devices. The stimulators look for TTL triggers, so in principle we could use the DIO ports to send those trigger events. The trouble is timing: we want the digital output to be tightly synchronized (again << 1 msec) with the analog i/o and to be able to specify the timing of those events to within 100 usec or so. I've put together a very dumb VI that takes as input an array of (bit pattern,time) pairs, then uses a While loop and Wait to manage that event list and Write to Digital Port to generate the trigger events. Since Wait is only 1 msec precision, and since we don't have a good way to synchronize with the analog i/o, we've got jitter in the trigger events of about 1 msec, which is too big.
One solution to the Wait resolution problem might be pattern i/o, but our board apparently doesn't do that. I have vague ideas about synchronizing the start of the digital and analog by setting the analog output to start on a trigger and having the digital side write that trigger value to start everyone, but in practice I haven't got that working yet. (A possibly related problem: though our scan clock is supposedly running through PFI5, if I hook an oscilliscope to that terminal on our BNC-2090, I don't see anything. I'm probably doing something stupid. Can anyone spot it?)
I'm new to LabView (though an experienced C/C++ programmer) and thus would greatly appreciate any advice or examples people could provide.
Thanks much,
Kevin

You are going to need some additional hardware to fully implement your problem. An interim approach would be to digitize the digital lines along with the analog data so that you at least have a corrolation of your existing data. The more complete solution is to use either a pattern generation board from NI or the DIO-64 board from our company. www.viewpointusa.com. With this board, you can "schedule" a digital pattern at a specific clock tick. resolutions to better than a microsecond are possible. The clock tick could come from the same clock that your are using. The reason your scope may not have seen the clock signal on your current setup is that the pulse is VERY short. your scope settings may not have been set to pick it up.
Stu McFarlane
Viewpoint Systems, Inc.

Using the same wire for positive edge start trigger and negative edge stop trigger for 6533

I would produce a start trigger for an external data source to start them.
Emediatly after this starttrigger this source produces a trigger Signal.
I would like to use this trigger Signal as an extern trigger which should provide some functions:
1. on the positive edge of the Signal some pattern should read in with an external clock.
2. on the negative edge of the trigger signal this process should stop.
I would do this with CVI

Hey Schicki,
I have included two links below that should help you with your application. The first one is setup to perform digital pattern I/O with an external clock in CVI. The second shows how to incorporate start/stop triggers in digital pattern I/O operations. You should be able to combine parts of these two programs to complete your application.
NI 6534 Double-Buffered Pattern Generation, External Clock -- CVI
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3E7FD56A4E034080020E74861&p_node=DZ52321&p_source=External
Output Digital Data from a Buffer to a Group of Two Digital Ports Upon a Digital Start Trigger
http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=B45EACE3EA4556A4E034080020E74861&p_node=DZ52321&p_s
ource=External
I hope this helps.
Regards,
Todd D.
NI Applications Engineer

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.

USB-6009 digital input change detection

Hi,
I am trying to acquire digital signals from an ni usb-6009 device using daqmx on labview 8.0. I need to write the signals from a port of the device to an output file only when there is a change in the signals and I am not able to do this successfully. I created a digital task in MAX and was able to select acquisition mode as '1 sample (On Demand) ' only. Any other selection for acquisition mode would result in error 200077 with the following message -
Measurements: Requested value is not a supported value for this property.
Property: SampTimingType
You Have Requested: Sample Clock
You Can Select: On Demand
I selected '1 Sample (On Demand)' acquisition mode and was able to see the channel values on running it in MAX as I rotated a device connected to the usb-6009 device. As expected the hex values on MAX were showing up as FF,7F,3F,BF and this pattern was repeated everytime I provided the input by rotating the device.
Next, I created a simple vi to use the digital task I setup on MAX. I want to be able to record the signals only when there is a change in the digital pattern from the channels.That is when there is atransition from FF to 7F to 3F and so on, the vi should write to an output file and if no change happens, it should not write to file. To do this, I explored the Timing vi and tried using the 'Change detection' mode, but that produced the same error as above.
Can anyone please suggest a way to accomplish what I am trying to do ? Any guidance will be a hugely appreciated.
Thanks
~Sej

All of that effort with sample rates, timing, change detection, etc ciuld have been avoided if you had read the specs. As you finally found out, the device only supports sftware timed i/o and no change detection. You wll have to do your change detection in software this is done with a shift register/feedback loop.

Create 4 digital output pulses base on input ttl signal

Hi
I am a beginner in Labview and would appreciate any advice on how to solve the following problem.
I am creating a TTL pulse train, and would like to send that into Labview as input. For every falling edge detected on the input signal, I'd like Labview to generate 4 digital output pulses. For each output pulse, I'd like to be able to specify the delay, and duration. The picture should illustrate it more clearly, with the numbers showing the intended order of magnitude.
System: NI PCI-6733 DAQ card, Labview 8.5
My daq card has 2 24-bit timers, and 8 digital I/O but I don't know what the best approach is for creating between 4-8 output pulses of this precision..should it be handled in hardware, or in software? And how would I go about it
Thanks,
-Sidney
NI Hardware: PXI-7853R, PCI-5122, PCI-6733, PXI-1036, PCI-MIO-16E-4, PCI-6110
Computer Hardware: Xeon Quad Core - 2.33 Ghz, 8 GB RAM
Software: Labview 2009, Labview FPGA 2009, Vista 64-bit, MAX 4.6, DAQmx 9.0, NI-SCOPE 3.5
Solved!
Go to Solution.

Hi Yann,
Wow, thank you so much for this example! I'm trying to take a look at it, but when I run it.. it responds with the following error message
Error -200452 occurred at Property Node DAQmx Trigger (arg 1) in DAQmx Start Trigger (Digital Edge).vi:1->reprise-1.vi
Possible reason(s):
Measurements: Specified property is not supported by the device or is not applicable to the task.
Property: Start.TrigType
Task Name: _unnamedTask<49>
This is strange too, because ive already used the Digital Edge Start trigger for a different application with this card.
-Sidney
NI Hardware: PXI-7853R, PCI-5122, PCI-6733, PXI-1036, PCI-MIO-16E-4, PCI-6110
Computer Hardware: Xeon Quad Core - 2.33 Ghz, 8 GB RAM
Software: Labview 2009, Labview FPGA 2009, Vista 64-bit, MAX 4.6, DAQmx 9.0, NI-SCOPE 3.5

Trigger-digital pattern

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