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

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
Digital Multimeters (DMMs) and LCR Meters
Programmable Power Supplies and Source Measure Units

6534 in Pattern Generation Input and Output

Hello All
I have a PCI 6534 High Speed Digital I/O card that I am trying to use to generate a pattern output from port A and acquire some data from port C. I have connected Port C, bit 0 to high and all the others low and I have also connected the two REQ pins together. This is to allow for the REQ pin from the pattern generation output to drive the input as an external clock. I have set the timebase as 1uS and the request interval as 10, to give a REQ pulse every 10uS. The idea being that the pattern generation output will generate a REQ pulse every 10uS and this would cause an input read to occur. My code can be found in the attached word file.
Now initially I placed the DIG_Block_In command before the DIG_Block_Out and set the two counts to 100. For a single run of the application this filled my input buffer array with 50 elements of 257.... which I think is what I would expect as for a count of 100 it takes 2 to fill both the upper and lower 8 bits of the input array. OK....
Now if I change the In Count to 200 and leave the Out Count at 100 I only fill 48 elements. I have no idea why this would happen. In my finall application I hope to increase the count to nearer 2000 and this loss of elements becomes significant.
If I swap the DIG_Block_Out command to go before the DIG_Block_In then with both counts set to 100 I get no data acquired at all. If I increase both counts to say 2000, I actually acquire 944 elements, 56 less than I would expect? Why is this....?? Is it because the DIG_Block_Out command has already started the process before the DIG_Block_In command is initiated?
Does anybody know what is going on here? I have had the same problem with a PCMCIA 6533 card (worse) and thought it would be solved with the PCI 6534. Does anybody know how I can ensure the correct numbers of data are acquired every time I run this operation? I need to be sure that all the desired data is being acquired as my final application is very dependent on this.
Any help would be gratefully appreciated.
Jamie
Attachments:
6534_Timing_Issues.doc ‏27 KB

Hi Jamie,
Whenever you are communicating from one group to the other on the 653x boards, you should have the input clocked on an external signal and you should have the output start AFTER the input process has started.
As for why your input buffer is half your output buffer, it could be that the intermediate PC memory buffer is in terms of bytes and your application buffer was casting this data to a 2 byte word.
I linked on one of your other posts 2 example programs. Adapting those might suit your needs best. Have a good day.
http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HFORCEKWTID=75069:5&HOID=5065000000080000008BA10000&HExpertOnly=&UCATEGORY_0=_31_%24_12_&UCATEGORY_S=0
Ron

Why does Start Digital Edge in Start Trigger.vi do a kind of timeout?

Hi I am doing a manual trigger on my hardwareboard by inserting a 5 volt source into the selected triggerchannel a couple of seconds after I push the start button.
The generation never starts. But if I put the trigger signalchannel equal to the external sampling clock the appended vi work.
Example I use PFI7 as trigger source which is also the source of the sampling clock.
Could somebody explain?
Kindest regards,
Lasse
Solved!
Go to Solution.
Attachments:
Cont Gen Voltage Wfm-Ext Clk-Dig StartA.vi ‏36 KB

One cannot just insert a wire with a 5 V potential to PFI6 for instance if PFI6 is used as a trigger for "Start Digital Edge" daqmx -vi. The pin is floating and just inserting 5V does not guarantee a low to high edge.
If I use a potentiometer to pull the channel low first, and then increse the voltage, the trigging happens.

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.

Pattern generation doesnt work - DIOHS96

Hello
I have a trouble getting the DAQmx to do a pattern generation as expected.
the first mode of operation, is when i set the clock configuration to "sample clock": the card should support 2MHz operation, however, above about 2KHz, the card spits out everything BUT the last 16 samples! . the error i get is underbuffer, when i force the task to stop after having waited too long. above 1MHz the output operation dies in the middle, underbuffer error.
to note, i monitor all the time the data written to buffer, and the actual nb of samples generated. i see that i have written a nb of samples, that the memory has filled, that it recovers as the data is spit out, and that suddenly, 16 bits from the end it stops.
the second mode of operation, is by setting the clock configuration to " burst (input)", after the recommendation of Johannes from this same forum (by the way, i still want to understand why first mode of operation doesnt work). then, on most computers installed with same card the system works nicely, and i get 2MHz operation working.
But for one computer: a new HP, which had a bug already not recognising the NI card first, but after the bug fix from knowledgebase it recognised it. it seems this card work using traditional DAQ now on this specific computer.
What happens on this computer is that the "sample clock" configuration works as on any other computer, meaning badly. and the "burst input" mode, doesnt work at all. it spits out only the first 16 samples, then dies. i have to stop the task manually.
so you can check that i make no mistake, i attach my piece of code that does the work.
Hope that i get help fast! thanks
OOPS! this should have gone to hardware board! - disregard!
Message Edited by Gabi1 on 05-10-2007 04:56 AM
... And here's where I keep assorted lengths of wires...

This will get you most of the way there:
       Pattern p = Pattern.compile(".+@[A-Za-z0-9\\-_]+(.com|.net|.edu)$");
       Matcher m = p.matcher(email);
       if (m.find()) { System.out.println("Match - Email Address OK"); }
       else { System.out.println("No Match - Email Address Bad"); }

AO output/start digital edge

AO output中，我想用DAQmx write来写入电压信息到buffer，然后用DAQ start task开始产生电压。我的程序中用start digital edge指定每个pulse的falling edge来开始产生电压。我的问题是电压是不是只有在pulse的low edge电压才能产生，而当下一个rising edge是，产生就会停止呢？还是说start digital edge只决定第一次电压写入的时机？望高人指点！

可以贴程序框图看看么？
Thomas | Xi'an China
LabVIEW 7.1 | LabVIEW 2011
DAQmx | CompactRIO

How to trigger temperature acquisition (6024E) at the start of signal generation from NI5411?

I'd like to begin/end acquiring temperature data with the 6024E after the start/stop of the signal output from the 5411. What is the best way to accomplish this? is software or hardware triggering better?

Rudy,
Using a hardware trigger is definitely the more precise method. I would suggest that you consider using markers from the NI 5411 to trigger the NI 6024E. Information concerning this topic is available in the NI Signal Generators Help. Specifically, it is available in the following location:
Contents >> NI Signal Generators Help >> Devices >> NI 5411 >> Waveform Generation >> Marker Events
If you do not have the NI Signal Generators Help, it can be downloaded from the following location:
NI Signal Generators Help (NI 5401/5404/5411/5421/5431)
Once you have exported the appropriate makers, numerous examp
le programs exist that demonstrate how to trigger the NI 6024E. If you are using LabVIEW, I would suggest that you examine the Acquire N Scans Digital Trig.vi example.
Good luck with your application.
Spencer S.

DIGITAL SIGNAL GENERATION

Hi!
I want to generate a digital signal (0-5V) in order to turn on and off an hydraulic pump. The time on (high) and time off (low) are specified by a MatLab code, so that once the pulse has finished one cycle, the program should be go again to MatLab code and take two times again. Then it should generate the signal again.
Thank you for the help.
Miguel

Thanks for the reply.
I have a system with an hydraulic pump, power supply, transistor and computer. I would like to send a digital pulse from my computer (0-5V) to the transistor. The transistor then closes a circuit (power supply and pump), and the pump starts running.
Then, I would like that each sample (each pulse) has specific width (time on), and also specific time off before it starts with other sample. These times (time on and time off) are computed by a MatLab code.
I'm working with DAQmx drivers and I also have a BNC 2110.
I also attach my code in Labview that I am trying to modify.
Thanks a lot.
Regards,
Miguel
Attachments:
Gen Dig Pulse Train-Finite_original.vi ‏22 KB

Starting digital edition 2.1

Hi,
I've a problem.
After installation successfully the program doesn't start.
I get the error-message:
"loking for online - help" or "close starting"
What must I do, to open it successfully?
Thx to the comm. for helping me.

One possible reason for the problem is that ADE2 versions are a load of untested rubbish.
Try using v1.7.2 instead and see if it helps.
~~~~~~~~~
There are lots of bugs in ADE2.0 (and 2.0.1). Try replacing ADE2.0 with the older but more reliable v1.7.2.
(You can have them both installed at once if you like.)
Version 1.7.2, it is a little difficult to find, available on Adobe site for Windows and for Mac.
http://helpx.adobe.com/digital-editions/kb/cant-install-digital-editions.html
The forum software is sometimes corrupting the link above. There shouldn't be a blank in 'editio ns.html'. The following redirects to the same page: http://tinyurl.com/diged172
Some people have found ADE trying to upgrade automatically.
It appears (not 100% sure) that if you install ADE2.0 as a new install (not as an upgrade) that your 1.7.2 will continue to run.
Probably best to say no if 2.0.x installation asks if you want to migrate your library.

Digital signal generation in cDAQ- 9477 with 1ms resolution.

I am using cDAQ -9477 Digital card with 9178 chassis (USB) .I have to generate some digital signals for 2 seconds. The signal should be
0 (3ms) - 1(1ms) - 1 (2ms) & repeat the sample 0 (3ms) - 1(1ms) ……. upto 2 seconds.
I had generated samples for 2seconds with 1ms duration of each sample.
I am unable to do that with 1ms resolution in cDAQ -9477 Digital card.
Is the above signal generation is possible (each sample -1ms) ?
I am using LabVIEW2009 .I attached the code.
Kindly let me know the suggestions .
Attachments:
Digital Signal.JPG ‏7 KB
Digital.vi ‏40 KB

cDAQ chassis do not currently support hardware timed tasks for digital modules with >8 lines. The DAQmx help defines these devices as "static digital I/O modules". The "Digital I/O Consideration for C Series Devices" section in the DAQmx help describes the capabilities of digital modules on different chassis.
Unfortunately this means you are stuck with static (software timed) generation. Over USB this will affect the accuracy of your signal. You won't be able to achieve the signal you are trying to generate with the current support. Static generation will max out at roughly 1kHz, but Windows can introduce a large amount of jitter. What you really need is a hardware timed task.
This is a feature that could be added in the future. I recommend submitting a feature request, though I know that doesn't solve your problem now.

ITunes won't start -- Digital signature the problem?

I haven't been able to get iTunes to start for the past month. It all started when I installed iTunes 7. I never had any problems with iTunes before that. I've tried nine or ten different suggestions and nothing seems to be working. Is there any way that I can delete iTunes 7 and somehow get back to using iTunes 6? This may be my last hope. I'm seriously considering buying a new computer just so I can use iTunes again.
Also, for the past few weeks, whenever I try to install software updates I get some message about the digital signature being incorrect. I am able to get the updates installed manually, but I was wondering if this digital signature issue could have something to do with iTunes not working anymore?
I've been using my Mac for the past three years and haven't really had any problems until now, so this is very frustrating. Thank you for any help or advice you can give me.

Check out the user tip below.
https://discussions.apple.com/docs/DOC-6562

Digital pulse generation

hey there, i am now trying to generate a simple pwm signal using digital write and read. so far, i've been trying to manipulate the square waveform and offset it so that it only goes from zero to one volts. den i would compare this analog output with a zero comparator whose output would be sent to NI-DIOwrite.this doesnt work at all. some help would be greatly appreciated. it would be best if there is a file that i can look into. thanks and regards

Right now you are trying to capture a digital signal right?
First, connect the output of the comparator to a oscilloscope which can capture single pulse, thus test your comparator.
If the output is correct, connect it to NIDIO, also probe the voltage there, if the output is not correct, then the channel of that DIO might break down.
If the output is correct, it will be the problem of your software, or unluckily the NI card.

High Speed Pattern Generation (32HS)

Hello,
I need to generate a string of logic 1's and 0's based on the value of various
knobs and switches on the front panel. Getting this streem out at 1 Mhz seems
to be a problem. I get errors when running my 32HS at 1 mHz saying that I have
limited bus-bandwidth and that the DAQ board has an underflow condition. My
question is, does anyone know how to give bus control completely over the the
DAQ board so that the transfer can complete?
Thanks,
Dave

Here is the detail explanation of the requirement...
I want to generate a finite pulse pattern of frequency 400 kHz , it would have a burst of pulses paving a period of 2.5 us and pulse width 0.5 sec , I had successfully generated true, fasle pattern out from DIO at lower frequencies (till 15 KHZ ) and subsequently used that to trigger the counter.
The problem..... if we want to achieve higher frequency from DIO ( 400 kHz) , it goes silent and no more triggering is available for counter to generate pulses .
The Patten picture is depicted below, I hope the problem has been elaborated more , if there is still any question do let me know,
regards to everyone

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

Re-start Digital Pattern Generation

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