Counter output cards

I am currently using PCI 6259 which has 2 counter outputs. Are there any counter cards that I can add to get 5-8 additional counter output? All the ones I see on NI and Measurement Computing website have maximum of two outputs.
Solved!
Go to Solution.

I like the idea of a low-cost USB device with counters.  If you have the chance be sure to fill out a Product Suggestion to help us prioritize, maybe it's something we could look into if demand is high enough.
In the meantime, you might want to look into the 9174 chassis which was just released 2 days ago.  It uses the same STC-3 chip as our X series devices, so it has 4 counters available on the chassis backplane.  To access them externally you would need to use a digital module such as the 9401. 
The 9174 connects to your computer via USB and is programmed using DAQmx (support added in version 9.0.2).
Best Regards,
John
John Passiak

Similar Messages

  • Synchronize two counter outputs on 6071E card

    Well, it's the usual how do I synchronize two counters problem.
    I'm using the 6071E with DAQmx .NET 4.0. I define a Task and attach to it two counter output channels with implicit timing and zero initial delay . When running the program
    I catch the first edge with a scope single trigger. There is always a delay between the first edge of ctr0 and the first edge of ctr1 of 16.3 microsecs. Is there a way, besides setting the initial delay of ctr0 to 16.3 microsecs, to make the counters to always start together? what is the source of the delay(software/hardware) and should it always stay constant.
    any help is welcome
    Solved!
    Go to Solution.

    The source of the delay is that despite being in the same tasks the counters are still started sequentially by software.  I'm surprised the delay you are seeing is constant.
    If you want the counters to start together you should configure a start trigger.  Once you start the counter tasks in software, issue the start trigger to begin generating your output pulses.  The start trigger must be a hardware signal--as an example you might configure a software-timed digital output and wire it back in to one of the PFI lines.
    If you want to avoid any additional wiring, you could split the counters into two separate tasks.  Trigger one counter with the internal output of the other (start the task that is going to be triggered first).  Doing this instead of using an external trigger, I would expect an additional delay between the counters on the order of 100 ns as the initial delay is at minimum 2 timebase ticks.
    Best Regards,
    John Passiak

  • Can I generate pulse trains on more than one counter output at the same time?

    I have a PCI 6601 card with a BNC 2121 to connect the signals to two devices. The card is used as a trigger for both devices and I want to be able to generate pulse trains on two output channels at the same time, with a time delay between the two. How do I do that in Labview 7.1 Development with DAQmx?

    I feel foolish for not being able to figure this out, but it still doesn't work. Attached is the VI I use now. Counter 0 generates a finite pulse train and I programmed Counter 1 to generate a retriggerable single pulse triggered by CtrOinternaloutput. I still get the same error message: -50103 The specified resource is reserved. The operation could not be completed as specified.
    The same happens if I set the trigger for counter 1 at PFI36 (default output of counter 0) or any other PFI line. If I try a pulse train generation on only one of the counters, both work fine.
    If I try the example in traditional DAQ for multiple counter outputs with phase delay, it works fine.
    Can you tell me what I'm doing wrong?
    Attachments:
    Shutter_AND_lamp_trigger.vi ‏103 KB

  • Counter Output/Counter Input PXI Signals Behaving Erratically

    Question for all your LabVIEW guru's out there,
    I am running a frequency loopback test using the NI PXI 6229 MIO DAQ card.  I am generating a "Counter Output" pulse train signal which feeds through my device under test and then back out of my device under test and back into the PXI 6229 for a "Counter Input" frequency measurement.  Both the "Counter Output" and the "Counter Input" are assigned different PFI lines using DAQmx in LabVIEW.
    I have 4 lines to test on my DUT.  All four lines run this same frequency measurement but with different PFI lines on the PXI 6229.  Each line is test independently.
    This is my setup for the 4 lines:
    Path 1: P2.0 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.1 (Counter Input - Frequency Measurement)
    Path 2: P2.2 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.3 (Counter Input - Frequency Measurement)
    Path 3: P2.4 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.5 (Counter Input - Frequency Measurement)
    Path 4: P2.6 (Counter Output - Pulse Train) -> DUT (Device Under Test) -> P2.7 (Counter Input - Frequency Measurement)
    where:
    P2.0 = PFI8
    P2.1 = PFI9
    P2.2 = PFI10
    P2.3 = PFI11
    P2.4 = PFI12
    P2.5 = PFI13
    P2.6 = PFI14
    P2.7 = PFI15
    I have a LabVIEW VI which generates the "Counter Output" and reads the "Counter Input" frequency.  I am seeing weird behavior from the PXI 6229 card. I can test "Path 1" and "Path 2" and the frequency I read is what I generated. No issue there. However, when I test "Path 3" and "Path 4" the frequency measurement is erratic.  The readings are two different frequencies repeated over and over again and none of those frequencies are the expected frequency which was generated out of the "Counter Output."  If I reset the card, and start by testing "Path 3" and "Path 4" the frequency readings are correct and the erratic behavior is gone.  However, when I try to then test "Path 2" and "Path 1" now those lines have the erratic frequency issue. I can continue resetting the card and see same issue. The PFI lines that I test first will always pass.
    To summarize:
    Steps Taken:
    1. Test Path 1 = SUCCESS
    2. Test Path 2 = SUCCESS
    3. Test Path 3 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
    4. Test Path 4 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
    5. Reset the PXI 6229 Card
    6. Test Path 3 = SUCCESS
    7. Test Path 4 = SUCCESS
    8. Test Path 3 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
    9. Test Path 4 = Erratic Frequency (Two Frequencies repeated over and over again in my frequency results array)
    I am wondering if Port 2 (P2.0-P2.7) on the 6229 card has certain dependecies and this is why I am seeing issues.  I am trying to get around this issue so that I don't have to always reset the card.
    Are P2.0-P2.3 (PFI8-PFI11) and P2.4-P2.7 (PFI12-PFI15) treated differently or require different setup?  How do I resolve this issue?
    Thanks so much!

    I have a theory...
    The DAQ card follows a policy called "lazy uncommit" wherein the terminal used for the output will continue to be connected to the counter even after the task has completed (until the terminal is needed for something else).  So as you run more tests, the counter output will end up driving more lines.  This behavior should be easy enough to confirm.
    As the DAQ card drives more lines, I'd imagine this affects the actual signal.  You could scope it to check, but it sounds like either the rise/fall times are becoming longer or some extra noise is being introduced on the line.  
    The readings are two different frequencies repeated over and over again and none of those frequencies are the expected frequency which was generated out of the "Counter Output."
    This implies you are picking up an extra edge during transitions--this isn't too uncommon if the signal is noisy since there is no built-in hysteresis on the DAQ card.  I would expect the measured frequencies to have periods that sum to either the full period or the semi-period of your actual signal (depending on how many duplicate edges are detected).
    Suggestions are as follows:
    To stop the DAQ card from driving multiple PFI lines, it would probably be easiest to just programmatically reset the device in between your tests (using DAQmx Reset Device).  If you can't reset the device (e.g. because you are running some other task that can't be interrupted) then you can instead configure a dummy task that uses the PFI line in question as an input.
    To stop the DAQ card from picking up multiple edges during transitions, you should configure a digital filter on the input terminals.  If you reset the device it sounds like this might not be necessary... it's up to you if you want to configure this or not.
    Best Regards,
    John Passiak

  • How to filter starttrigger on counter output precisely

    HW PCI6602
    Measurement studio 2008 (C#)NI-DAQmx 9.02I’m trying to trig a camera using the output from a counter.
    The camera should be trigged when the counter input pulse width is larger than approx (filterPulseWidth 10us).To do this a have set up the following tasktask.COChannels.CreatePulseChannelTime(counter,                "TriggerTaskChannel", COPulseTimeUnits.Seconds, COPulseIdleState.Low, 0, 80E-6, 0.007);             task.Triggers.StartTrigger.Type = StartTriggerType.DigitalEdge;            task.Triggers.StartTrigger.DigitalEdge.Edge = DigitalEdgeStartTriggerEdge.Rising;             task.Triggers.StartTrigger.Retriggerable = true;task.Triggers.StartTrigger.DigitalEdge.DigitalFilterMinimumPulseWidth = filterPulseWidth;            task.Triggers.StartTrigger.DigitalEdge.DigitalFilterEnable = true;Unfortunatly this filter has the following behaviour”If the period of the filter clock timebase is tfltrclk, this filter guarantees topass pulse widths that are 2*tfltrclk or longer and to block pulse widths thatare tfltrclk or shorter. A pulse with a width between these two ranges may ormay not pass, depending on the phase of the pulse with respect to the filterclock timebase”.It means that I have no sharp distinction on my filter as one would when applying a filter to an ordinary pulse width measuring task. Implementing this with via the software in a callback is to slow.The bottom line is that I would like to generate a pulse on my counter output when the trigger/counter input is greater than say 10us. The output pulse could be predetermind as in the sample code above or as long as the filtered input (I.e counter just pass filtered input to my output).How can this be done? BR
    Jongas
    Solved!
    Go to Solution.

    Hi Jongas,
    Is it OK if the trigger is sent once the pulse hits 10 us, rather than
    on the exact falling edge?  I'll assume the exact timing isn't as important, but you would like the trigger to occur very close to the falling edge (within a couple of us).  The important thing is that we trigger as close as possible to when the PWM has hit 50% duty cycle.
    Some brainstorming:
    Digital Filtering on the 660x Isn't the Best for This:
    Digital filtering might not be as practical here on your 6602 due to the region of uncertainty between 5 and 10 (or 10 and 20) us pulses.  The TIO boards count two consecutive edges of a filter clock to determine when to pass a signal through so the guaranteed rejected pulse width is always half of your guaranteed passed pulse width (providing an external filter clock timebase that is synchronized with your external signal could potentially reduce this uncertainty but I honestly haven't tried this before and I would imagine it is not going to be very straightforward).
    X Series Alternative:
    Our X Series devices use a different method of digital filtering that would work better for you.  If a hardware change is an option (and you can use PCIe) then you might consider this.  You could use the 20 MHz timebase as your filter clock timebase and could guarantee to pass 10 us (200/20M) and reject 9.95 us (201/20M).  The 6320 is currently our lowest cost X Series board.  A couple of points about this solution:
    1.  To configure the PFI filter, you need to use some sort of dummy task to
    access the property nodes.  Here is an
    example of this (although it is written in LabVIEW).
    2.  You can route the filtered PFI signal to be exported on another PFI line, but this will reserve Counter 3.  This is documented in the Device Routes tab of Measurement and Automation Explorer.
    3.  The filtered output will be 9.95-10 us delayed from the input signal, so you could trigger the camera off of the rising edge of the filtered output directly and be fairly close to the actual falling edge.
    External AND Gate Alternative:
    You could configure a Counter Output to generate a re-triggerable pulse with a 10 us initial delay (to be triggered off of the rising edge of your PWM signal).  Assuming the pulse is short enough to complete before the next period of your PWM signal, the counter output would only be high at the same time as the PWM signal if the signal was longer than 10 us.  Use the external AND gate to combine these two signals and the result would be the trigger for your camera (the rising edge would correspond to 10 us after the PWM signal first goes high).
    If you wanted to you could make the counter output pulse a little longer (say 8 us) and trigger the camera off of the falling edge out of the AND gate (a.k.a. rising edge out of a NAND gate) which would line up with the exact falling edge of the PWM signal.  Don't make the CO pulse too long or it will overlap with the next period of the PWM.
    Another Idea:
    One idea that I keep coming back to is to use the internal rollover event of a counter input task (a pulse is generated whenever a counter rolls over on its Internal Output which can be routed to a PFI line).  I don't think this will work, but the idea in theory would be to:
    1.  Set Default state to known value (e.g. 2^32-200).
    2.  Gate the Counter so it only counts during the time PWM is high.  Have it count the 20 MHz timebase.
    3.  Reset the Counter to default state on the falling edge of the PWM signal.
    4.  The counter would rollover if 200 pulses occurred of the 20 MHz timebase (10 us), and the Counter Output could be routed to a PFI line to trigger the camera.
    The problem is that there is no good way to reset the counter except for an encoder measurement (Kevin has already made a nice suggestion about this).  A Pulse Width Measurement would technically reset the counter, but you cannot currently set the default value of a Pulse Width Measurement task so there is no way to make the rollover happen prematurely).
    Configuring an encoder measurement and working with the multiple counters on the 6602 to produce appropriate A,B, and Z signals might be a method to look into further, but at this point I think you'd be better off with an external AND gate.
    I don't want to say it's impossible with just the 6602, but I can't think of a straightforward way to go about it without external hardware (although maybe I can sleep on it and think of something later... how many counters do you have to work with?). 
    With your current NI Hardware, I think your best bet is to go with an external AND gate.  If you're planning on purchasing an X Series card the digital filtering idea is actually not a bad way to go.
    I hope this is helpful!
    Best Regards,
    John Passiak

  • How to Immediately Change Counter Output Rate?

    I have a piece of code that largely works like this example: http://zone.ni.com/devzone/cda/epd/p/id/5493
    In other words, I set up the Counter Output with some initial frequency and duty cycle, but then during the main loop of my program I continuously change the frequency to a new value based on other criteria.
    I'm using an M-series PXI card and LabVIEW RT.
    The problem I'm having is that the card waits for the next edge before changing the counter output rate. For instance, lets say it is going at a low frequency and I am upping to a high frequency. If the command arrives in the middle of the current pulse, it will wait to complete the low-rate pulse before starting the high frequency output. Is there a way to make it interrupt the current count and immediately start counting at the new rate?
    Thanks,
    Isaac

    Hi Isaac,
    I posted the code in LV 8.2 so you should be able to open it now (it sometimes takes several minutes to upload).
    There are a few limitations to using the digital lines instead of the counters:
    1.  The digital lines are updated off of a sample clock which will be much slower than a timebase.  For example, on the 6221 the maximum update rate is 1 MHz, while the counter output has a max timebase of 80 MHz. As a result, the number of frequencies you can generate are going to be more restricted (divide down from 1 MHz vs. 80 MHz).
    2.  On M series devices, the digital lines must be clocked from an external source.  This could be generated from a counter
    3.  You have to build the digital waveform, which is a bit tricky (I think the example code should help out with that but I haven't had time to thoroughly test it).
    4.  If you are generating digital lines at fast rates, you will need to write quite a few samples at a time to the output buffer to ensure the data does not underflow.  If the buffer includes multiple periods of the digital signal, you would have the case that using the counter output would still update more immediately.
    Again, to determine the best course of action it would be useful to know what frequencies you want to generate and which exact hardware you are using. I just mentioned the digital lines as an alternative to the counters, but it might not be ideal for your situation.
    -John
    John Passiak

  • Variable frequency counter output

    I found this example of how to vary the frequency of a counter output, but it appears this is not supported and i receive the following error. Can anyone tell me if there is an alternative method at all? my device is a usb6341 which has 4 COs
    thanks
    Attachments:
    Capture.JPG ‏118 KB

    If you found that code in an NI-provided example, it's probably more likely that the operation is not supported by your specific hardware.
    What is the range of frequencies you want to create?
    How accurate does the clock need to be?
    How often will the frequency be changing?
    Can the hardware receiving the clock tolerate and "discontinuities" in the pulse train?
    You could momentarily stop the clock, change the setting and then restart it.
    MIke...
    Certified Professional Instructor
    Certified LabVIEW Architect
    LabVIEW Champion
    "... after all, He's not a tame lion..."
    Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

  • "loopback" counter output without wiring

    Cross posted from another forum for more visibility:
    Basically, I have a counter output being generated on a trigger line. It's just a pulse at defined intervals of 1 hz. The problem is, the card that is generating the output needs the trigger itself, but if it is using the trigger line to output the trigger itself, it can't read it. I know I can get around this with a timing and synch card, and possibly with external wiring, but is there any way to do this all in the backplane?
    In summary, can I have a AO card generating a counter output on a trigger line use that output as a trigger for itself in some way, without extra wiring or a 6672 card?
    CLA, LabVIEW Versions 2010-2013

    Jeff·Þ·Bohrer wrote:
    Greg,
    What are you really triing to do?  your post is a bit more cryptic than usual.
    My instinct says "a single board RIO" would do the trick.  but, that's a lot of capability to throw at a simple PFIO line.  What did you get yourself into this time?
    NO NO NO. No sbRIO. Did NI pay you to help market now?! 
    All I want to do is have a digital pulse, which I can use as a start trigger for ALL my AI and AO. Some tasks stop and restart while others keep running continuously. When the select tasks restart, they need to sync back up with the continuously running tasks, and they do so by using this start trigger again. This is not a clock sync, think of it like a "wait until next ms multiple." I resolve this by having a digital pulse happening every "x millseconds" which I use as my start trigger. If a task restarts, it will again wait for this pulse.
    The problem is, if I am generating this trigger on PXI1Slot12/PXI_trig0, I cannot also trigger off of this trigger line in slot 12.
    CLA, LabVIEW Versions 2010-2013

  • Setting the counter output mastertimebase divider?

    Hello
    I want to output single short pulses with varying pauses. My MuFu DAQ card has 20 MHz master clock rate and 24 bit counter (Good ol'6052E). When I try to output 1 µs with a pause duration of more than 839 ms, I get an error due to mismatch of clockrate and counter bit size with short and long duration. This is explained in great detail in the corresponding help:
    2/ counter clock rate <= X <= 2^24 / counter clock rate. with counter clock rate = master clock rate / divider
    0.1 µs               <= X     <=   16777215 / 20Mhz = 839 ms
    I could strech my limits by manually setting the CO.CounterTimebaseMasterTimebaseDivider to 10. But I've searched all property nodes I could find but I have not found this property.
    Does anyone know where it is hidden, and to which values it can be set?
    Thank you
    Michael

    Hi Michael,
    Unfortunately that property doesn't exist.  There are a few "Divisor" properties available for other subsystems (e.g. see Analog Input timing block diagram below).
    However, you'll notice in the above diagram that the valid divisors of the master timebase are only 1 or 200 (which then gives the AI Sample Clock Timebase).  You can get similar behavior on the counter by specifying to use the 20 MHz timebase or 100 kHz timebase for your source.  However, using the 100 kHz (1/10 us) timebase is going to prevent you from properly generating the narrow 1 us pulses that you require.
    So, you can use 20 MHz or 100 kHz without any additional resources, but 100 kHz wouldn't allow you to have a 1 us pulse, and 20 MHz won't let you have a high or low time of greater than ~839 ms.  You could generate frequencies in between these to use as the counter timebase (either use the frequency output or use the second counter to generate the desired frequency, or perhaps configure a dummy analog task) but of course there would always be a tradeoff between the resolution of the pulse and the maximum time between pulses.
    If you do have the 2nd counter available, here is my suggestion to get the best of both worlds:
    1.  Configure a counter output to generate a pulse every N seconds (I suggest configuring the output to generate at 1/N frequency at 50% duty cycle).  When you configure this counter, DAQmx will choose an appropriate timebase for you.  When N is less than ~1.67 seconds, DAQmx will use the 20 MHz timebase (since both the high and low time would be under the 839 ms).  When N is > 1.67 seconds but below ~335 seconds, DAQmx will use the 100 kHz timebase.  If you intend on modifying the rate of the output (to something above 1.67 seconds) after the task has started you would need to make sure to specify to use the 100 kHz timebase rather than relying on the DAQmx default.  You can't use a built-in timebase if you want to generate a delay greater than 335 seconds, but if you wanted to you could handle this case by checking for it and configuring the frequency output to generate an even lower timebase.
    2.  To generate the actual output signal, configure a retriggerable single pulse generation to be triggered off of the signal generated above.  This signal will be based off of the 20 MHz timebase (assuming you configure a pulse width less than ~839 ms) and so will give you a good resolution on the available pulse widths that you can generate.
    In summary, doing this would let you decouple the resolution of your generated pulse width from the resolution of the delay between the pulses.  The downside is that it uses two counters.
    The other option which I previously mentioned (and what you were asking about) would be to find a timebase that meets the two requirements: 1) fast enough to generate a narrow pulse and 2) slow enough to not roll-over between pulses.  You have 100 kHz and 20 MHz available to you, but you can generate intermediate frequencies using the frequency output.  If you plan on using a counter to generate the timebase instead, you should consider the other option which decouples the two counters.
    Of course, using a device with a higher counter resolution (most newer DAQ devices use 32-bit counters) would probably also resolve your issue depending on the full range of  delays that you need.  The downside here is the cost of new hardware.
    Best Regards,
    John Passiak

  • Changing the PXI-6624 Counter Output rate on the fly

    I'm programming an application in VB.net 2005 to set several counter output channels (each with its own task) on the PXI-6624 card. I'd like to know if there is a way to change the frequency of the output without stopping the task, changing the frequency and restarting the task. I'm using the PXI-6624 card to simulate encoders and speed sensors.
    Thank you very much,
    JonS101

    Hi,
    Yes, you can change the frequency on the fly. Here is a knowledgebase that will give you an insight of how you should approach this matter. How Can I Change the Duty Cycle on My Continuous Pulse Train? To find this property node and how to use it refer to the DAQmx .NET reference: Where Can I Find NI-DAQmx Property Node Listings and Help?
    I hope it helps
    Jaime Hoffiz
    National Instruments
    Product Expert
    Digital Multimeters and LCR Meters

  • Counter Output

    Hello
    I am using DAQ PCI 6221 card for analog inputs and outputs, I am using both the counter outputs for controlling temperature, by putting heaters On and Off through the digital pulse train I am getting from counter outputs.
    But I am having a problem with the counters that even if I change the Low time and High Time the pulse I get just dont changes accordingly,
    changes timing effects from next time when I run the VI, I am attaching the VIs(CTR1.vi and CTR0.vi are similar just change the channel name) involved in this, first I am acquiring the temperature and then comparing it with low and high limits and taking an action whether to On or Off heaters.
    High Time and Low time are required because as soon as I reach near to set temperature I increase the Low time and vice versa.
    Could anybody please tell me where I am wrong??
    Attachments:
    Show Alarm SV.vi ‏14 KB
    CTR1.vi ‏37 KB
    Dig Pulses2.vi ‏117 KB

    Are you trying to change these values once the task has started running?  Consult this KB for information on how to do to this:
    "Why Can't I Change the Duty Cycle on My Continuous Pulse Train?" 
    To summarize, you'll need to use DAQmx channel property nodes to set the pulse width and frequency.
    Elijah Kerry
    Senior Product Manager, LabVIEW
    Follow my Software Engineering for LabVIEW Blog

  • Disconnect counter output line

    Hello,
    I have a question that has been bothering me for awhile.  I'm using an M-series DAQ card which allows the ctr0 output to be placed on any PFI line.  Is there any way to disconnect the ctr0 output from all the PFI lines?  I'm only using the ctr0InternalOutput and I don't want it routed to an external pin.
    The reason I ask is because the ctr0InternalOutput was being used as timing for several acquisitions, but the output was also appearing on it's default output pin.  However, this DIO/PFI line was being used as a digital output for relay control and every time the counter was used, the relay would switch.  I "fixed" it by routing the counter output to an unused PFI line, but I would like it not to appear externally at all.
    Thank you for your help,
    Jon

    Thanks, I will give that a try.  Seems so obvious now...
    Jon

  • Two counter outputs with 90deg phaseshift

    Hi,
    I have NI PXI-1042 chassis and two NI PXI-6513 digital output cards in it.
    Task is to create two pulses with 90degrees phaseshift.
    Is there function in labview 7.1 which generates pulses descriped above. I`m meaning that if I tell function to count up, signal A is ahead signal B and if A is 90 degrees behind B it means counting down?
    Is there way to do this by connecting 3 (signal A, signal B and GND) counter wires all in one counter and controlling only one counter to "count output down" or "Count output up"? 
    - Santtu

    Hi Santtu,
    I think I understand what you are trying to do. 
    Essentially you have two counters, but you want to be able to control their
    phase relationship to one another.  This is definitely possible to do;
    however, there are not many examples dealing with it.
    I did find one Traditional DAQ Example (non- M-Series) that
    might help you out with this: Twin
    Pulse Train Generation with Variable Phase Shift Control
    Traditional DAQ uses an older API, so I would recommend you look at the
    attached example over this example.  Just wanted to give you more
    than one option.
    As far as it 'counting' up or down, that really would have
    to be done by a counter input task.  Since the input would be the same as
    that for a quadrature encoder, then you would use the methods described in my
    previous post.  As the output it will simply look like two different
    counters.
    For the best solution though, I went ahead and created an
    example for you.  It shows how to generate 2 different counter pulses that
    are out of phase with one another by a specified amount of time. 
    Hope this helps,
    Otis
    Training and Certification
    Product Support Engineer
    National Instruments
    Attachments:
    Gen Dig Pulse Train-Continuous-Dig Start-Phase Shift.vi ‏82 KB

  • Pause the counter output in DAQmx

    Hi~
    I used two counters output on PCI-6602 card in LV7.1 to generate a PWM to control the velocity of two motors that control the position of mechanism.(Encoder was set on the motor.)
    When I set the same duty cycle in two counters, the position of two mechanisms were different(Two mechanisms were the same),that means one velocity of motor was fast, the other was slow.
    May I pause the counter output of the fast motor to wait the slow motor??
    ====================
    ●LV Version：LabVIEW7.1
    ●OS：WindowsXP(SP1)
    ●Hardware：PCI-7344, PCI-6602, PCMCIA 6024E

    Assuming you're using DAQmx, you can set up a Pause Trigger for each of the counters.  (A similar function can be done in traditional NI-DAQ too).  You could, for example, configure 2 different digital bits to be used to pause the 2 PWM counters independently.  The way 'Pause Triggering' works is that the counter's pulsetrain only goes to the output pin when the pause trigger signal is in the correct logic state.  This can be set to be low or high by programming. 
    You may also want to characterize the speed difference of your actuators, and give them correspondingly proportional PWM duty cycles.  That would do a better job of keeping them in sync throughout the motion.
    A feedback signal would give you even better options for control.
    -Kevin P.

  • Bus communications for 660x counter timer cards

    I believe I have a new application for 660x counter timer cards. I propose to build some additional circuitry on a blank PCI card to be installed in the same PC as the 660x card. If my sequence of pulses is generated on my home-built card, can this pulse sequence be fed via the PCI bus to the 660x card or must the 68 way connector be used. Can the PCI 6602 use the PCI bus for data receipt and transmission? Can the PXI 6602 use the PXI bus in a similar manner? Please note, my application will still be viable if the PCI/PXI bus cannot be used in this manner but it would give me more options and probably a 'cleaner' solution.
    Thanks and regards.

    Hello,
    This sounds like a really interesting project. I�m not exactly sure what the details of your application are, but I can tell you that the counter input and output signals are only available on the 68-pin connector of the 660x card.
    If there are any other questions you have about this card or how to interface to it, please let me know.
    Have a great day!
    Ken S.
    National Instruments

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