Compteur TTL

Bonjour, j'ai essayé de compter les fronts montants à partir de la broche ND_PFI_3 sur laquelle j'ai injecté un signal TTL, mais je ne sais pas comment spécifier sur quelle période je souhaite compter.
Mon programme de comptage est le suivant :
GPCTR_Control (1, ND_COUNTER_1, ND_RESET);
//Selects the application for which you use the general-purpose counter.
GPCTR_Set_Application(1, ND_COUNTER_1,ND_SIMPLE_EVENT_CNT);
GPCTR_Change_Parameter(1, ND_COUNTER_1, ND_SOURCE, ND_PFI_3);
GPCTR_Change_Parameter (1, ND_COUNTER_1, ND_SOURCE_POLARITY,
ND_LOW_TO_HIGH);
GPCTR_Change_Parameter (1, ND_COUNTER_1, ND_INITIAL_COUNT, 0);
GPCTR_Control(1,ND_COUNTER_1, ND_PROGRAM);
GPCTR_Watch(1,ND_COUNTER_1, ND_COUNT, &compteur);
printf("le compteur compte %d \n",compteur);
GPCTR_Control (1, ND_COUNTER_1, ND_RESET);
Merci si on pouvait m'aider, surtout me dire quelle fonction utiliser pour préciser la période de comptage d'un simple signal carré.
je pense qu'il faudtrait que j'utilise les fonctions
GPCTR_Change_Parameter (1, ND_COUNTER_0, ND_GATE, ND_IN_START_TRIGGER);
et
GPCTR_Change_Parameter (1, ND_COUNTER_0, ND_GATE, ND_IN_STOP_TRIGGER);
mais je ne sais pas comment configuer les start et stop , car quand j'essaie ils me disent "invalid action"......
Merci par avance.

Bonjour jorjio,
Pour utiliser les lignes numérique, il vous faut des niveaux TTL.
Cordialement
Rémi D.
National Instruments France
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>> Les rencontres techniques de NI - Mesures et acquisition de données : de la théorie à la mise en ...

Similar Messages

NI 9401 - lecture simultanée de compteurs

Bonjour,
je suis en train de mettre en place un stand d'acquisition d'une pompe à chaleur. J'utilise le matériel suivant :
Labview 2010, v10.0
1x NI-cDAQ-9188 avec modules : 9263, 9481, 9435, 9207 et 9401
1x NI-cDAQ-9188 avec modules : 9217 et 9213
Mon programme est construit de la façon suivante : Une boucle cadensée tourne toutes les 2 secondes, à l'intérieure de cette boucle, une structure en séquence opère différentes actions : affichage, lecture canaux, calculs (bilans d'énergie), régulation, sauvegarde.
Tout fonctionne bien sauf l'acquisition du module 9401 (comptage de 4 compteur à impulsions TTL).
En fait, j'ai deux problèmes :
Le premier est que je n'arrive pas à compter simultanément les quatres compteurs TTL installés sur le module 9401. J'ai essayé tous les exemples donnés sur labview de compteurs, sans succès.Lorsque j'essaie, l'erreur suivante apparait :"Le périphérique ne peut pas être configuré en entrée ou en sortie car des lignes ou des terminaux qui lui sont connectés sont utilisés par une autre tâche ou une autre connexion. Cette opération nécessite que toutes les lignes et tous les terminaux soient temporairement réservés à la communication, ce qui interfère avec l'autre tâche ou connexion...."
Le second problème est que, comme est construit mon programme, la séquence ne permet pas de lire en continu mes compteurs pour "voir" passer les impulsions et les totaliser.
Pour information, le comptage séparé de chaque compteur fonctionne lorsque j'utilise "Count digital Events.vi"
Quelqu'un aurait-il un exemple de vi ou des pistes que je pourrai explorer...
Un grand merci d'avance
cath

Bonjour Florian,
un grand merci pour votre aide.
J'ai adapté le vi "DAQmx Digital Input and Output and Counter Input with NI 9401" pour mon application et ça marche... presque... Je m'explique :
Lorsque je le lance la première fois, ça totalise parfaitement sur mes 4 compteurs. Si je l'arrête (au moyen de la commande STOP du vi), je n'arrive plus à lancer le programme et la même erreur qu'avant apparaît, c'est-à-dire l'erreur code -201133 (à DAQmxStartTask.vi). En pressant continuer, continuer, continuer, le programme s'arrête. Je le relance, je refait continuer, continuer, continuer...le programme s'arrête. Après 5 tentatives, le programme s'est lancé sans erreur ! Il doit y avoir un problème dans la gestion des tâches, mais franchement, ça me dépasse un peu...
Avez-vous une idée de la cause ?
Je mets en fichier joint mon vi.
A bientôt
Cath
Attachments:
DI-DO-CI with 9401 - Cath.vi ‏28 KB

Type de sortie d'encodeur (TTL, open collector,...) que le compteur peut acquisitionner

Bonjour,
Je me cherche un encodeur rotatif que je veux acquisitionner avec ma carte USB-6008. Je suis un peu confus avec tout les types de sorties offers. J'ai l'impression que c'est une sortie TTL (voltage en référentiel) qu'il me faut et non pas "Line Driver" (voltage en différentiel). Est-ce que je peux utilisé des encoeur de type "open-collector" et si oui, les NPN ou PNP. Merci de votre aide.

Bonjour jorjio,
Pour utiliser les lignes numérique, il vous faut des niveaux TTL.
Cordialement
Rémi D.
National Instruments France
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>> Les rencontres techniques de NI - Mesures et acquisition de données : de la théorie à la mise en ...

Counting rising edge during 50ms for a TTL signal

Hello, I'm using Labwindows 6 and a traditionnal DAQ. I've injected a TTL signal on my card and I would like to count the number of rising edge each 50 ms without using an internal timer in labwindows so that the counting pace cannot be disturbed by Windows.
Do someone know how to process or which functions should I use?
Thanks

Hi it's still me with still some troubles
I've generated with my counter0 a square wave of 50 ms pulse width from an internal source but then, I don't know how to specify that this signal will also be the pin gate (ND_PFI_4) of my counter1 which will count the rising edge.
Moreover I also don't know how to specify my counter1 just to count rising edge while my gate is at high state; here 's mys code :
    //Generation of an internal 100 KHZ square wave
    GPCTR_Control(1, ND_COUNTER_0, ND_RESET);
    GPCTR_Set_Application(1, ND_COUNTER_0,ND_PULSE_TRAIN_GNR);
    GPCTR_Change_Parameter(1, ND_COUNTER_0, ND_SOURCE,ND_INTERNAL_100_KHZ);
    //Generation of a 100 ms gate
    //50 ms => low state
    //50 ms => high state
    GPCTR_Change_Parameter(1, ND_COUNTER_0, ND_COUNT_1,5000);
    GPCTR_Change_Parameter(1, ND_COUNTER_0, ND_COUNT_2,5000);
     //output the counter pulse, you must call Select_Signal.
    Select_Signal(1, ND_GPCTR0_OUTPUT, ND_GPCTR0_OUTPUT,ND_LOW_TO_HIGH);
    GPCTR_Control(1, ND_COUNTER_0, ND_PROGRAM);
    //configuration CPTR1 that will count each rising edge while the gate is at high state
    GPCTR_Control (1, ND_COUNTER_1, ND_RESET);
    GPCTR_Set_Application(1, ND_COUNTER_1,ND_SIMPLE_EVENT_CNT);
    GPCTR_Change_Parameter(1, ND_COUNTER_1, ND_SOURCE, ND_PFI_3);
    GPCTR_Change_Parameter (1, ND_COUNTER_1, ND_SOURCE_POLARITY,ND_LOW_TO_HIGH);
    GPCTR_Change_Parameter (1, ND_COUNTER_1, ND_INITIAL_COUNT, 0);
    GPCTR_Control(1,ND_COUNTER_1, ND_PROGRAM);
    GPCTR_Watch (1, ND_COUNTER_1, ND_ARMED, &compteur);
    printf("%d\n",compteur);
And the value of compteur is not the value expected at all.
thanks.
(ps : can you speak french?)

6601 4 compteurs

Bonjour,
J'utilise une carte compteur 6601 (4 compteurs) pour la mesure de position de front montant ou descendant sur une entrée gate d'un compteur.
J'utilise également un programme test labview 6.1 nommé Count-int (DAQ-STC).vi qui me fournit la durée cumulée d'un niveau que l'on choisit.
Seul problème, j'ai besoin de la durée des deux niveaux pour mes calculs et j'ai besoin des 4 compteurs pour 4 signaux TTL distincts (je ne peux pas utiliser un compteur pour chaque niveau et pour chaque signal (cela ferait 8 compteurs nécessaires).
Comment

Bonjour,
Malheureusement, la mesure de largeur d'impulsion, ou mesure de semi-période (ce que vous appelez mesure du temps d'un niveau) monopolise un compteur. Si le compteur est configuré pour mesurer le temps à l'état haut, il vous faudra un autre compteur pour mesurer le temps à l'état bas.
Cordialement.
Matthieu, National Instruments france

How to acquire analog signal and send a TTL pulse at the same time based on PXI 6123

Hi,
I am using a PXI-6123 data acquisition card, as the picture show in the attachment ,I want to acquire the analog signal of ai0 through reference analog window and at the same time send a TTL signal to trigger my camera. I have tried two methods, one is using the DAQmx Export signal.vi another is using DAQmx connect terminals, but when the data acquisition card acquire the analog signal, the DAQmx Export signal.vi and the DAQmx connect terminals sometime can send an TTL pulse ,sometime can not.
I don’t know why? or some other method that can achieve my arm is appreciated.
Regards
chunlei
Attachments:
method export signal.vi ‏21 KB
method connect terminal.vi ‏36 KB
Send a TTL pulse.JPG ‏288 KB

Hi,
Have things changed over the years?
I need to syncronise a digital output (Modul NI9474) and an analoge input (AI-Modul NI9203) module. I need to measure time intervals from a flank in signal A to a flank in signal B. I would like accuracies of the order of 1 ms. Currently, the signals are not synchronised, with errors of the order of 2 times the block length (block size x sample rate), sometimes much higher. The best I got so far was a block size of around 20 with a sample rate of 1 kHz.
If I use the master and slave settings on the RTSL settings, my program doesn't run properly.
If I use digital signals for input and output, I can syncronise them with RTSL settings and everything is good, but I can't always do that.
Also, if I do anything in the GUI (such as scrollowing something or going to another window), my output gets screwed up properly.
1. What can be done to synchronise AI with DO?
2. Is there something that can be done to avoid messing up the output when something happens in the user interface? (I know that I am messing up the outputs as they make some valves switch and that is loud).
Thanks in advance!

How to send TTL output AND acquire AI voltage data using USB-6211

Hello,
I am relatively new to Labview, so please bear with me. I have a research application involving 2 pressure transducers and a high-speed camera. I wish to acquire analog voltage data from the 2 pressure transducers. However, at the start of the acquisition, I will need to send a single TTL output to trigger the camera. This TTL pulse must be sent out at exactly the same time that the AI acquisition begins, in order to ensure that my 2 pressure measurements and camera images are 'synchronized' in time.
Is this possible on the USB-6211 running with LabView 8.20? I currently have a fairly simple LabVIEW vi that uses a software trigger to start an AI acquisition - I have attached it with hopes that it may help anyone willing to assist me. I would prefer to be able to simply add something to it so that it will output a TTL pulse at the start of the acquisition.
Thank you in advance.
Regards, Larry
Message Edited by Larry_6211 on 12-19-2008 11:24 AM
Attachments:
USB6211_v1.vi ‏212 KB

Hi All,
I'd like to clear a few things up. First, you'll find that if you try to set the delay from ai start trigger and delay from ai sample clock to 0, you'll get an error. Due to hardware synchronization and delays, the min you can set is two. Note that when I say two, I am referring to two tick of the AI Sample clock timebase, which for most acquisitions is the 20MHz timebase. I modified a shipping example so you can play around with those delays if you want to - I find that exporting the signals and looking at them with a scope helps me visualize what is going on. The Manual has some good timing diagrams as well but it looks like you've already hit that. The defaults would give you a delay of 250ns from the start trigger - is this too high for your situation? What is an acceptable delay? I tend to think that "exactly the same time" is a measure of how precise rather than an absolute (think delays in cable length making a difference.)
With all that in mind, I see a few options:
Start your camera off of the AI start trigger (an internal signal) and just know it is 250 ns before your first convert.
Export the convert clock to use as a trigger. This assumes your camera can ignore the next set of convert clocks.
More complicated option: Internally you have an ai start trigger, sample clock and convert clock. From your start trigger to the first convert is 250ns but if you export your convert clock you're going to get future convert clocks as well. One option would be to generate a single triggered pulse using a counter (start with the Gen Dig Pulse-Dig Start.vi example) with the AI start trigger as the trigger for the counter, an initial delay of 250 ns, and a high time of whatever you want it to be. This should give you a singe pulse at very close to same time (on the order of path delays) as your first convert clock.
Hope this helps,
Andrew S
MIO DAQ Product Support Engineer
Getting Started with NI-DAQmx
Measurement Fundamentals
Attachments:
Acq&Graph Voltage-Int Clk.vi ‏37 KB

How can I use a TTL signal at my PFI to start a VI

Hello,
I am writing a VI to controll a motor with Digital Output, this is working. But this Vi has to start after the first (second, third or fourth) TTl pulse. How can I do that? I see some trigger options by AI and AO Vi's. But these Vi's are for different purposes.
Is there a simple way to "receive a pulse and than start a VI?
Thank you.

Hi wilco,
If you don't mind a slight delay on the order of a couple ms then you could simply poll that bit in software and start your sub-block when that line becomes true.
If you require more precise timing, you could use a counter and configure an interrupt to fire on the output of the counter. You would need to setup the counter for pulse generation and then configure the "pulse spec 1" register with the number of pulses you want to wait before you output (will have to be more than 1 on a counter though). DAQ Occurrence 4 will be the one you want to configure an interrupt for rising edge of a counter output. The LabVIEW help file describes these occurrences and you should also be able to find some examples using occurrences in the shipping examples.
None of them use event 4 but you can get the basic programming concept by looking at the examples.
Anyway, hope that helps. Have a good day.
Ron

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

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

CANNOT CONNECT iPhone/iPod touch to WIRELESS INTERNET wi-fi - (TTLS vs WEP)

Hi. I bought the iPod touch on the day it came out; took it home, it all worked fine.
At home i have a wireless router, and it supports the WEP format. so my iPod connects to the internet perfectly.
the day i took it to school was the day I got very disappointed at Apple.
My school, Concordia University, supports only the TTLS format, because it provides better security. But not the iPod touch, nor the iPhone support TTLS, they only work with WEP!
So naturally, i'm not able to connect to the internet using my iPod, and i found out everybody else who has an iPhone has the same problem.
what's even more surprising is that most of the hotspots (95% of them) downtown also work only with TTLS. apparently it's a newer technology. You can imagine how frustrated i was when i was unable to use my iPod touch for one of it's main functionalities.
So why doesn't the iPhone or the iPod touch support this ????
it's such a simple and necessary function, and yet they decided not to put it on ...
So I ask Apple to include TTLS support in the next iPod/iPhone software update.
And everybody else who owns an iPod touch / iPhone should also let Apple know of this serious lacking in their firmware.

Ya i have to admit, i'm very disappointed right now. I'm really close to getting n iPod Touch but because of this situation, their's no way in **** i'll be spending that money without it working at my university (Concordia).
This is not an admin problem at my university. They're using a protocol (like many others) to protect their users from crooks and such. Doesn't it make sense to think that the majority of iPod users, go to school? Of course it does. I don't get how this "authentication" was dropped easily like this.
Unfortunately, Montreal is infested with TTLS format (which the OP has already mentioned) and that blows at the fact that iPT doesn't support it.
All students are crying out to Apple right now because of this, Guys! Make it happen, please!

What hardware should I use for TTL synchronization?

I am searching for a hardware recommendation. Here's what the hardware should do: notify a PC program to run a subroutine upon detection of a TTL pulse (digital input change).
So I need one 1-bit digital input, and the device should communicate with a computer via USB. The TTL pulse voltage is about 4.7 V. Since the synchronization must be fairly precise, the delay should be on the order of 1 ms or less. Therefore the hardware should have a sampling rate of at least 1 – 10 kS/s.
I purchased the USB-6501 not realizing that it doesn't have any triggering or interrupt functionality, and now I don't think it will work for my application. I could constantly poll one of its inputs with my software to check for a change in value, but that would be relatively slow and hog my CPU. I would prefer that the device triggers or provides some kind of interrupt to my software application. I am considering using some NI software, but right now I'm using the session-based interface of the Data Acquisition Toolbox in the latest version of Matlab (R2013a, 64-bit) on 64-bit Windows 7.
I think either the USB-6008, USB-6009, or USB-6525 might be a good option, but I'm not sure. I don't fully understand the difference between the triggering/interrupt capabilities of the USB-6008/9 and the USB-6525. Any advice?
Solved!
Go to Solution.

Hello Brinmr,
i do not hava license for matlab so i can not test it.
On this page you found the supported NI hardware and here is the information the 6008 can be
used in session mode Supported Hardware - National Instruments- NI-DAQmx
and if i understand the function startForeground correct is this a session mode function.
You can made some tests with a simulated 6321 or 6251, but if this also not works then you should contact
the mathworks to ask them how you should implement your functions with mathlab.
best regards
Alexander Glasner
AE NIE

TTL signal vs TCP-IP, parctical and timing considerations

We have just purchased a BioPac MP1 50 physiological recording system (www.biopac.com). We would like to start/stop an acquisition from another computer system and/or to add annotations and markers.
To this end it seems there are two routes to consider. We could either use the built-in Trigger in/out capability with TTL signal of (0 and +5V square pulse) or use TCP-IP client-server to control it remotely (i.e. using VIs such as TCP-IP Listen). In the later case, I�d use the Beta LabView API libraries that BioPac is about to release for the MP150, instead of the dedicated AcqKnowledge 3.8.1 software, which is really good.
Because we need to correlate event during the physiological recording of our experim
ent, it would be ideal if the resolution were of ms accuracy (i.e. latency less than 1ms) and we need to manage up to 16 trigger channels.
I have very little technical background knowledge on this. Thus, in order to help me evaluate a solution, I would appreciate any comments and suggestions.
1) I would like to know first if anyone could recommend an easy solution to generate TTL signal (0 � 5V logical pulse) on both Windows and LINUX PC?
For instance I read about using the 25-pin parallel port, but I am curious to learn about other possible alternative such as USB, USB2 with or without adapter but also a very cheap card (a couple $100 max). I am already ruling out serial connection, because I am told it is very slow and has horrendous latency.
2) What are the latencies in read and writing/issuing TTL signals com? How does it compare with a dedicated byte stream through TCP-IP, on a dedicated cable and on a network cable?
3) Are they any VI application that you c
ould share to show how LabView 7.0 can talk through the respective ports to generate a pulse forming the trigger information being written or read in?
I look forward to hearing your feedback and suggestions. Many thanks in advance.
Donat-Pierre LUIGI

Use TTL. It is likely that the TCP/IP messages will get there fast enough
and that the software will respond in a timely manner but there is no way to
be sure. It is the fastest way to get from your LV application to your
other device. You may need to check the response time that the BioPac will
give to the TTL input verses a TCP/IP message.
You should also consider the level of programming needed to accomplish your
tasks. I would strongly suggest that you get a seasoned LV programmer on
the job or you will be wasting a lot of time and enduring needless
frustration.
The parallel port will respond is sub-millisecond. You should be able to
toggle it several hundred times in a millisecond. I've had LV applications
use the printer port for this type of communications before. I don't
remember the bandwidth but it's more than adequate for this application.
TCP/IP will sometimes get delayed by the OS (either Windows or Linux) due to
other things that are happening at the time which you don't have control of.
The message should go out in very short order (again sub-millisecond) but
there is no control over this.
Good luck,
Chuck
"Donat-Pierre" wrote in message
news:[email protected]...
We have just purchased a BioPac MP1 50 physiological recording system
(www.biopac.com). We would like to start/stop an acquisition from
another computer system and/or to add annotations and markers.
To this end it seems there are two routes to consider. We could
either use the built-in Trigger in/out capability with TTL signal of
(0 and +5V square pulse) or use TCP-IP client-server to control it
remotely (i.e. using VIs such as TCP-IP Listen). In the later case,
I'd use the Beta LabView API libraries that BioPac is about to release
for the MP150, instead of the dedicated AcqKnowledge 3.8.1 software,
which is really good.
Because we need to correlate event during the physiological recording
of our experiment, it would be ideal if the resolution were of ms
accuracy (i.e. latency less than 1ms) and we need to manage up to 16
trigger channels.
I have very little technical background knowledge on this. Thus, in
order to help me evaluate a solution, I would appreciate any comments
and suggestions.
1) I would like to know first if anyone could recommend an easy
solution to generate TTL signal (0 - 5V logical pulse) on both Windows
and LINUX PC?
For instance I read about using the 25-pin parallel port, but I am
curious to learn about other possible alternative such as USB, USB2
with or without adapter but also a very cheap card (a couple $100
max). I am already ruling out serial connection, because I am told it
is very slow and has horrendous latency.
2) What are the latencies in read and writing/issuing TTL signals
com? How does it compare with a dedicated byte stream through TCP-IP,
on a dedicated cable and on a network cable?
3) Are they any VI application that you could share to show how
LabView 7.0 can talk through the respective ports to generate a pulse
forming the trigger information being written or read in?
I look forward to hearing your feedback and suggestions. Many thanks
in advance.
Donat-Pierre LUIGI

Intel Mac OS X can't connect using 802.1x with TTLS authentication

To login at the wireless network on my school I use the following settings:
802.1x connection with TTLS authentication and TTLS inner authentication set to PAP.
My MacBook Pro logs in, but has a self assigned ip-address and I can't use the network.
On my old iBook and my friend's Powerbook with exact the same settings it works perfect. (and gets an assigned ip-address throug DHCP.
Bug in the Intel version of Mac OS X I guess?

Regarding the post about other intel macs being unaffected, I don't have an imac so I don't know for sure, but the connectivity problems seem to be more widely reported for the macbooks. It's certainly possible they are affected as well, but I was under the impression they were using a different chipset and/or firmware. (note to self, check on that).
What I cant understand is why they have changed the
airport express card for the intel macs, albeit the
processor has changed but that shouldn't affect the
card as that should be processor
The intel macs were largely designed by intel. I suspect that apple provided case dimensions and a specifications list which intel then used for the designs. The wireless cards in the powerbooks were based (iirc) on a pc-card bus. The older airports were based on PCMCIA-16.
In the macbooks, it appears to be a mini-PCI-express. (I had to send my back for noise issues. ASP might tell you what bus it connects to). The benefit to this is better speed and the possibility of future expansion. Dell uses the same connector.
Some side-benefits of having the board designed by intel (or with heavy intel involvement) is that we can already dual-boot windows XP. Wireless seems to work fine if you run windows on the macbook. Therefore, I think this is a driver issue likely to be resolved sooner rather than later.

How to send a ttl signal with a good exactitude less than 10ms?

i have a pci 6013 (8 input channel) and pci 6711 (4 outpout channel).Then i need to send a ttl signal to a camera ccd to take a photo when a waveform sinus is equal at zero (rising), but when i send this TTl signal with dasylab using generator pulse or combi trigger and readind this signal, i have difference between dasylab pulse(that is exactly) and measurement pulse that is approximate 40ms after.But i need to have less than 10ms is it possible?
Frequence rate =1000hz and block size=512 the waveform sinus is 0.2Hz.i have already try to increase the sampling rate but nothing happens.Thank for your help.

Yes, it's possible.
You just have to reduce your block size to 10 !
For more informations, visit Forum Dasylab en français at http://forum.aceboard.net/?login=128657
Frédéric Miqueau
MD Electronic, France
http://www.mdelectronic.fr
French Dasylab Forum : http://www.dasylab-forum.de/forum/index.php?showforum=43

Compteur TTL

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