How do I output a 10MHz TTL pulse in a PCI6251

As title,
第一次用麼高頻的輸出,
盼有好心人解答
感激不盡
已解決！
轉到解決方案。

請到 ni.com>>search>> correlated do
也就是透過 6251 >>DO 輸出 10MHz clock
不過 PCIe-6251 會比 PCI-6251 好些 ( 因為 PCIe bus 比 PCI bus 快 )
或是 counter output

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Attachments:
ttl.vi ‏26 KB

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Hi,
In the example I gave you, you need to supply the TTL you want to count the pulse (connected on pin 37) and a TTL "clock" which is connected to PFI0. The TTL on PFI0 permits a hardware timing (100ms for example) to count the edges that occur on the TTL source.
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Hope it will help you,
Regards,
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01-02-2006 01:26 PM
Attachments:
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How do I get the difference in time using 2 ttl pulses

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Hi Hideya,
As is the case with many programming questions, there are several ways to go about solving this one. The solution I have in mind is to poll the digital input line for a transition from low to high. The simplest way to do this would be to use a loop with a shift register to store the previous digital input value. When the current digital input value is greater than the previous value, you can get the tick count (microsecond resolution sounds like it would be sufficient). You can then do that sequence of operations a second time. The difference between these two tick counts can be used as the input to the wait (microsecond) function. After that you can send your digital output pulse.
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How to count TTL pulse by DAQ through BNC 2090?

I'm trying to count the TTL pulse from a APD by DAQ. There are some very nice discussions about this issue in this board. However, I am a novice and not sure about the hardware connection. The signal from APD is delievered out through a BNC cable and I'm trying to deliever this signal to DAQ through BNC 2090. I tried just simply connect the BNC cable to ACH0 and tried running the vi's, such as "Count_Edges.vi" and "Count_Events.vi". But I got no counts. I noticed that both these vis are actually reading signal from PFI port. That could explain why I got not counts.
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Hi Opal,
Here is what you should do for the hardware connections with these devices:
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That is all that is involved with the hardware connections. After this, you should be able to read your signal. Here is the link to a helpful DAQ manual with in depth getting started information: DAQ Getting Started Guide. I hope that you find this information helfpul.
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Can analog outputs simulate a 60hz ttl pulse?

The only outputs free on my 6020e are 2 analog. I need to drive a TTL device at 60hz. Can the analog outputs do this?

Paul;
You can do that but keep in mind that will not replace the counter pulse train generation operation. I'm saying that because the counter will execute a hardware operation, and so, will be able to have a completely system independent operation, generating a nice and accurate TTL pulse train.
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Roman Zeylikovich

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Thank you for contacting National Instruments. While using a motion controller would be the recommended approach for any type of motion application, you may be able to use your DIO board to generate a TTL pulse train to control the step and direction inputs of your drive and motor. You will need to make sure that the current sinking and sourcing specification for the DIO-96 fits your stepper motor. That board is not designed to source very much current at all so this is one issue you will need to verify. Also, this board does not have any counter/timer logic that can handle quadrature encoder inputs.
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CLA, CPI, AIA-Vision
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Attachments:
Trigger outgoing pulse based on position.vi ‏58 KB

Triggering with the DAQ card:
The 6229 unfortunately doesn't support analog triggering. Comparable cards which do are the 625x or 635x (also the more expensive 628x and 636x). On such cards there is an Analog Window Triggering feature that would produce the exact signal I think you are looking for (see X Series user manual). So if you have one of these handy or are looking to acquire new hardware then this would be a good solution.
Software detection for trigger signal:
If you want to continue using the 6229, see if something like the following would give what you want. Keeping the loop simple might help make this approach usable for your application depending on how long the window is you are looking for. It still isn't as reliable as a hardware-triggered approach.
External circuitry:
The simplest external comaprator circuit would just consist of an op-amp. You could use the analog output to set the threshold. The comparator output could trigger a counter output which would issue a pulse of some pre-defined width. The issue here is that the output signal would not be high during your exact window, but rather a fixed amount of time starting at the beginning of your window (so if the speed is changing it might not be what you are looking for).
You could in theory just build your own external circuit to generate the exact window trigger as well at which point you wouldn't need to output anything from the DAQ card (except for perhaps control voltages for this circuit). If you're at a university perhaps you could look for a EE student that you might be able to contract the work out to?
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I want to create a TTL pulse. The stepper motor I'm trying to control responds to a high to low edge, when the low pulse width is greater than 0.5 microseconds. What is the best way to go about creating a pulse like this?

I'm using the NI PCI-6025E card connected to an SCB-100 wiring peripheral. I'm programming the DAQ card using LabVIEW 6.0.2 on a win95 box.
My first attempt has yielded some surprising results.
I created a vi with a single while loop set to true. Within that while loop is a two frame sequence. Both frames use the "Write to Digital Line.vi".
The first frame sets the line in wire to false.
The second frame sets the line in wire to true.
The device channel on both frames has been set to my user defined channel nam
e -> clock.
clock --> sets the DIO0 channel to be digital write out.
Using an oscilloscope and some wires I hook ground to the SCB-100's digital ground and I hook the probe to the DIO0 channel. What I see are two different pulses alternating between one another. One has a pulse width of 5ms and the other has a pulse width of about 50ms. You seem to get a grouping of one type of pulse followed by a grouping of the other type of pulse.
Obviously this is very strange and not what I want. It is also far too slow. So I'd like to know if anyone knows how to do this properly. Remember I only need a low pulse width of 0.5 microseconds.
Thanks,
Any help or guidance would be much appreciated.
Scott

Scott,
You don't need to use a digital line to create a TTL pulse. The PCI-6025E has two onboard general purpose counters. You can use one of these counters to create a single pulse of the desired pulse width. For an example of how to program the counters on your board, refer to LabVIEW's Search Examples>>I/O Interfaces>>Counters>>Pulse Generation>>DAQ-STC based.
The advantage of using a counter over the digital line is that it allows you to control the timing of the pulse through hardware and not software. Thus, it is inherently faster, and the timing resolution is more accurate. The counter will count down an internal 20 MHz timebase to create the pulse delay and the pulse width.
For more information on the hardware capabilities of your board, you can refe
r to the User Manual online at www.ni.com/manuals.
Hope this helps.
Regards,
Erin

How can I output up to 7 tracks simultaneously?

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I have to create a little effect for an upcoming party. For this I need to output the following:
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Budget for this box is very limited, hopefully less than $200. Quality does not have to be very high although a good bass response will be important for the effect.
Thank you very much for any help.
Bo

Thanks for your help, HT. Would Logic be a better choice than ProTools LE for this? (I know next to nothing about them I must confess...)
I was just thinking, in the worst case scenario, I could just create the 6 audio tracks in GB, then output three stereo mp3 files (stereo front, stereo rear, 2 control tracks), dump each on a separate cheap mp3 player and get a controller that can remote start all of them at the same time...
Does anyone know of such a cheap mp3 player that can be remote started via a wire connection to a relay? Is there another forum that deals with this kind of issue?
Thanks again.
Bo

Wiring a SCB-68 to measure the frequency of a TTL pulse signal

Sorry if this is a basic question but could someone please help me and tell me how to wire up a SCB-68 connector block (connected to a AT-MIO-16 DAQ board) so that I can measure the frequency count of a series TTL pulses (signal from photon counting). At the moment I don't understand how the PFI1-9 connections are related to the GPCTR0/GPTR1 counter connections on the block and how they're all realted to the source,gate and out 1-5 connections on the DAQ board.
Ultimately I want to be able to put this measured frequency into a Labview program with a controllable gate period.
Thanks in advance
Nick

You might want to search the Knowledge Base on the NI's Support Pages for "Cable Mapping for a 68 Pin Connector to a 50 Pin Connector". This should take you to a link that will explain the mapping of a 50way to 68way cable and subsequent lines you are looking for ( reference sub link 68F50M), I guess you have SH6850 cable connected from the AT-MIO16 card to the SCB-68.
Please check out the information about the pin outs, that should help you work out which pins map to the counters, eg GPCTR0_source would be pin 37 on your SCB-68
Regards
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Can I send a TTL Pulse in a given rhythm?

I am new to LabView and using version 8.1.1.
I am trying to send a series of TTL pulses in a particular rhythm, (a train of 3 pulses at 50Hz repeated every 200ms). Is it possible to do this with accuracy?
Each pulse need to be accurate to the millisecond.
Thank you in advance.

Hello Lanny22,
Lynn is correct. If you have hardware timed (correlated) digital lines then you can do this by using the values he suggested. If you're using a National Instruments multifunction DAQ device with LabVIEW then I would recommend looking at this example program. Open LabVIEW and go to Help» Find Examples. Then navigate to Hardware Input and Output» DAQmx» Digital Generation» Cont Write Dig Port-Ext Clk.vi. This is the example program I would use to generate this pulse train.
Cheers,
Brooks

Need to generate a TTL pulse of 3 ms using USB Daq 6361

Hi all,
I need to generate a TTL pulse of 3 ~ 5 ms to trigger my external device. I am using USB daq 6361 with BNC connectors. I tried to use this examples(attached) but was not succesfull , can any one help me out in this, I just want a TTL pulse out to trigger my device. I tried to modify the example to see the wave form out but all it shows is a straight line. I want to generate a TTL pulse as soon as my program starts.
Am I using wrong example? should I use somethis else to generate the pulse. please let me know.
Thanks,
Attachments:
Capture.PNG ‏76 KB
Digital - Continuous Output_ttl.vi ‏65 KB

AnkitG wrote:
Jeff·Þ·Bohrer wrote:
Why would you create an Task with an analog output? its a Digital line you want to drive! and, just create it in the project.
Hi Jeff,
thanks but I couldnt understand , what you meant by create in project? Can you please explain. should I create digital line but I am still getting the same error.
Creating DAQmx items in Project Explorer saves the DAQmx object properties as part of the *.lvproj file. This can be very useful when the Task configuration does not change in the built application and you seldom want to use the task elsewhere. If you want to make minor tweaks to configuration of the run-time app there is even a human readable text file in the build output where properties like scale offsets, timing rates or ranges can be modified without redeploying a new app.
Jeff

How do I output a 10MHz TTL pulse in a PCI6251

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