Pulse width timing /demodulation

Hello,
I'm trying to use labview 7.1 to simulate the behaviour and acquisition of a counter timer board.
I've created a VI which generates a frequency modulated pulse train using the signal generator VI's
and used the timing and transition measurement VI to get the pulse period. Unfortunately, the timing/transition
VI only seems to give a measurement every time the while loop iterates (about once a second), rather than measuring the period of every pulse.
Is it possible to measure the period of every single pulse (with a carrier frequency of around 1000-2000Hz)
to obtain the demodulated signal in Labview?
I've only been using the Labview demo version for a few days so I'm no expert...
thanks!
Tim

Tim,
If you're going to be working with a TTL-compatible pulse train, the most straightforward solution is to use the hw counter/timers available on the multifunction boards. I've done some apps with a similar carrier freq and the good news is that you can get a reasonable quantization error on your measurements -- 1 part in 10k-20k, which is better than the 1 part in 4k you'd get from a 12 bit analog measurement.
The data acquisition should be done with a counter timer programmed for buffered period or frequency measurement. Under DAQmx, you'd use a DAQmx Timing vi set for "Implicit" to let the pulse train edges act as a variable-frequency sampling clock. You may also need to use a DAQmx property node to specify the appropriate timebase -- on E series you'd want the 20 MHz rather than the 100 kHz. Then the intervals you measure will count ~10k - 20k timebase cycles per cycle of your external pulse train, leading to a fairly low quantization error.
Post back if you need more info on using counter/timers. In the future, you might want to put signal and hw related questions in one of the hw boards. It's probably more likely to get answered sooner.
-Kevin P

Similar Messages

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

NI6602 pulse width measurement: Do I have to use an external sample clock?

Hi
In the .NET 4 example 'MeasPulseWidthBuf_SmplClk_Cont' it is stated in the comments that:
An external sample clock must be used.
Counters do not have an internal sample clock available. You can use
the Gen Dig Pulse Train-Continuous example to generate a pulse train on
another counter and connect it to the Sample Clock Source you are using
in this example.
I have an application running without specifying an external clock. The applications is running, but I'm not sure I can trust the recorded data. Here is the channel creation code:
   task.CIChannels.CreatePulseWidthChannel(readTaskCounter,
   "ReadPulswidthTask", 25e-9, 20e-6,
   CIPulseWidthStartingEdge.Rising,
CIPulseWidthUnits.Seconds);
task.CIChannels.All.DataTransferMechanism = CIDataTransferMechanism.Dma;
   task.Stream.Timeout = callbackTimeoutInMilliSeconds;
task.Stream.Buffer.InputBufferSize = 50000;
   task.SynchronizeCallbacks = true;
   task.Timing.ConfigureImplicit(SampleQuantityMode.ContinuousSamples);
   task.Control(TaskAction.Verify);
Note that I'm not specifying any external clock.
1) Which clock is the daq using? -It is obviously using some clock since I can collect data via this task.
2) Do I need to change the configuration to use an external clock to achieve reliable readings - as mentioned in the 'MeasPulseWidthBuf_SmplClk_Cont' example?
/mola
Solved!
Go to Solution.

Hi mola,
That specific example is for sample-clocked pulse width measurements. This type of measurement is only supported on newer hardware such as X Series boards and will not run on the 6602.
Your application that you linked uses Implicit timing, meaning that the signal itself serves as the sample clock. That is, at the end of each pulse width that you measure, the sample is deterministically latched in. So, you end up with a buffered array of every pulse width that is seen by the counter.
Best Regards,
John Passiak

How can I configure the CTR 1 GATE to output a pulse (10us long) and then immediately take a pulse width measurement?

I'm using the BNC-2120 DAQ and LabVIEW for interfacing with an ultrasonic position sensor. The sensor is the "PING))) ultrasonic range finder." It measures the distance from PING))) to some object directly in front of it. It has 3 pins (5V, ground, and a signal pin). The 5V and ground are easily taken care of with the 5V and digital ground outputs on the DAQ. The signal (SIG) pin works in the following way:
1) Send a 10us, 5V pulse to SIG. This triggers PING))).
2) Wait 200us. PING))) takes a distance measurement.
3) SIG outputs a square wave with a specific pulse width.
The pulse width varies with the distance of the object away from PING))). I've tried using CTR 1 OUT to generate the pulse, and then using CTR 1 GATE to measure the pulse width. However, the measurement is stuck measuring 0V because CTR 1 OUT is on the same pin! So PING))) tries to output a pulse, but cannot due to the fact that CTR 1 OUT forces the SIG voltage to be 0V. So I need to use just one counter I/O line to trigger and measure. How can I do this?

Hi Matttastica,
What DAQ
card are you using? The reason I ask is that the PFI lines on some cards can be
used as PFI lines and digital I/O lines, while on others they can only be used
as PFI lines. The pinouts and diagrams for our cards can be found at www.ni.com/manuals. You can accomplish
what you are looking to do if your PFI line is a DIO lines as well.
I would
suggest doing two tasks, one for counter output and one for counter input.
(Note that both these are not going to be the same line). The counter output
will be used to do a single pulse generation, while the counter input will be
used to read back the period.
This will
work because, at first, we are going to route the line from the counter output
to the counter input line by using a ‘DAQmx connect terminals’ (basically
making the input line an output line for a moment). First, setup the tasks and
the DAQmx connect, start the tasks and have the counter output do a ‘wait until
done’ to ensure the pulse is sent. After this is done, do a DAQmx disconnect
terminals (turning the input back from an output to an input), and then do a
DAQmx read for your counter input (period measurement). You may look at the
shipping examples for pulse generation and period measurement in LabVIEW (Help »
Find Examples... » Search tab … search for examples)
One note is
that since this is software timed, it may not be fast enough to meet your 200us
timing. If this ends up being the case, please look at the 6552, as it can do
per clock cycle direction change very fast.
David L.
Systems Engineering
National Instruments

How to generate and output 3 TTL square waveforms with different pulse widths using counters of NI 6034E

Hello
I just have a few questions.
I am using the NI 6034E DAQ board in order to
generate simultaneouly 3 different TTL digital signals, with different
pulse width, and output these TTL signals to an external circuit that I
am using for this application.
The following pattern of the TTL pulses will look like this:
01010101 01010101
00110011 00110011
00001111 00001111
From
what I understand, I have to use the 2 counters, Ctr0 and Ctr1, to
generate the TTL pulses that I desire, because the DIO lines are
software timed only and I will not be able to produce a deterministic
output period using these DIO lines. Am I correct?    Also, do I have
to use a separate counter to generate a separate TTL digital pulse. I
need 3 different TTL pulses and there are only 2 counters for this DAQ
device. The three generated TTL signals will be feed to an external
circuit. Concerning the hardware connections for my application, I
assume that the generated TTL signals will be output from
GPCTR0_OUT(pin 2) for counter 0 and GPCTR1_OUT(pin 40) for counter 1
of the NI 6034E. Is this correct? Is there any way that these TTL
signals can be output from three DIO lines(DIO0...2).
Here is some code that I plan to use in order to do this:
#include <NIDAQmx.h>
static TaskHandle gTaskHandle = 0;
DAQmxCreateTask ("", &gTaskHandle);
DAQmxCreateCOPulseChanTime (gTaskHandle, "Dev1/ctr0", "", DAQmx_Val_Seconds, DAQmx_Val_Low, 1.0, 2.0, 2.0);
DAQmxCreateCOPulseChanTime (gTaskHandle, "Dev1/ctr1", "", DAQmx_Val_Seconds, DAQmx_Val_Low, 3.0, 4.0, 4.0);
DAQmxCreateCOPulseChanTime (gTaskHandle, "?????", "", DAQmx_Val_Seconds, DAQmx_Val_Low, 7.0, 8.0, 8.0);
DAQmxCfgImplicitTiming (gTaskHandle, DAQmx_Val_FiniteSamps, 5);
DAQmxStartTask (gTaskHandle);
DAQmxWaitUntilTaskDone(gTaskHandle)
DAQmxErrChk DAQmxStopTask(gTaskHandle)
DAQmxErrChk DAQmxClearTask(gTaskHandle)
I believe this code should generate the 3 TTL square waveforms that I want for my application.
Please provide me with some feedback. It would greatly be appreciated.
Thank You

Hi,
The NI 6034E is a multifuntion DAQ device, this means you have:
(2) counters
(8) DIO lines (software timed)
(16) AI, single ended
(0) Analog Output
You have a couple choices here:
   1. Software timed digital output of all three signals, max 1khz loop rate, non-deterministic.
   2. Hardware timed digital output of 2 signals, max 20Mhz.
   3. Hardware timed digital output of 2 signals and software timed digital output of 1 signal.
   4. Find another NI MIO board such as the NI 6251. This board will do 10Mhz pattern generation for (8) DIO lines.
For the hardware connection, you are correct, the output for the counters will be taken from pin 2 & pin 40. Here's the pinout for the NI 6034E for reference:
The output of the Counters can be routed to some of the PFI's or to the RTSI connector. You can see this in MAX
Message Edited by Matthew W on 11-19-2007 01:24 PM
Attachments:
2007-11-19_131609.jpg ‏61 KB
2007-11-19_132435.jpg ‏86 KB

How to generate a pulse train with different pulse width and delay?

How to generate a triggered pulse train with different pulse width. for example, after each trigger signal, let's say 2 ms, then the counter output a pulse with pulsewidth of 1 ms, and then after 3 ms delay after the first pulse, the second pulse was generated with a pulse width of 4 ms. Next cycle when the trigger signal comes, the same two pulses will be generated and so on. Is it possible to achieve this by using 6601 counter card? and if yes, how to achieve this? Thanks!

Unfortunately you can not create a hardware timed pulse train with different widths on each pulse from a counter. Whilst it can be changed on the fly using software, since you require a hardware triggered signal getting the software involved will not give a huge amount of accuracy when the pulse will actually change.
So in short you can't use your 6601 card (or a counter timer) to achieve this
There are three possible Alternative solutions
1 You could use a high speed digital IO device such as the (6533/34) to generate your variable signal which would require setting up the pulse train as a series of states based around the burst transmission mode where the clock would give you your specific timing.
2 A timed analogy output (for example on a MIO card with a clock (PCI-6220 / 62xx), i.e. Not the 6704 style static analogy output cards)
3 A high speed digital waveform card such as the (, 656x , 655x, 654x, 6534, 6533 (http://www.ni.com/modularinstruments/find_right.htm) ) this could then be scripted to work with your triggering and also there is a digital waveform editor which will enable you to set up the pattern you wish to generate (http://sine.ni.com/nips/cds/view/p/lang/en/nid/13555)
Hope that helps
Tim Matthews
NI (UK)

Finite pulse train with variable pulse widths

Greetings LabVIEW developers,
Does anyone have code that can show me how to use E-series counters to generate a finite pulse train where the individual pulse widths vary? I need to generate a series of 20 pulses with the high time for each pulse randomly varying between 50 and 1000 microseconds. The low time for each pulse needs to be constant (around 50 microseconds).
Thanks,
Ryan Wright

Ryan,
Sorry, but this isn't possible with the counter/timers. I've been wanting this capability myself for about 6 years now.
Personally, I think it's an unfortunate "hole" in product capability. The other major data acq hw allows you to capture and later replicate a signal of interest. You can capture an analog waveform with AI and later play it back with AO. You can capture a digital pattern and later play it back with timed DIO. You can capture buffered semi-periods with a counter -- but you can't play play them back later. So for your app, you'll need to generate the variable freq using timed DIO. The new M-series boards ought to work for this, or a dedicated high-speed digital board.
There's another product that I think is even better for timed DIO though and it's put out by one of NI's "Alliance partners" -- Viewpoint systems. Here's an example of why I like it. Let's say you need to generate 20 pulses within 60 seconds. The times of the pulses need to be precise to within 1 usec, and they have no common divisors. The NI method will require you to use an update rate of 1 MHz and you'll create a buffer of 60 MB to represent the digital pattern at every usec. The Viewpoint method needs a buffer of 40 entries. Each entry is a combination of a timestamp and a pattern to generate at that timestamp. That pattern will just stay there until the next defined timestamp. So all you do is define the digital pattern at the instants when one or more bits will change. It works analogously for digital input - if you capture with 1 usec resolution for 1 minute but there are only 20 pulses (40 digital transitions), you only capture the 40 relevant timestamps & patterns instead of a full 60 MB.
If interested, look for the PCI-DIO64 at Viewpoint's website.
-Kevin P.

Wiring hardware for pulse width measurement

I am in difficulty.even with so simple pulse width measurement.
I am using labview 7.1, DAQmx, MAX, PCI - 6220.
I cannot find help document as to how to measure PW measurement and I find no connection diagram in MAX for using pulse width measurement.
I connect to PFI 9 (Gate) to 5V via switch. What about timebase counter as source? Ok I wanted to use internal clock from PCI-6220. But I cannot get to measure PW.
I want to MAX to measure. Once it is ok, then I will build a simple vi to understand its working better.
Pls help.

Hello,
LabVIEW has examples that are located in the Example Finder under the Help menu inside of LabVIEW. The examples specific to pulse width measurement are organized and located under the Browse tab of the Example Finder under the folders <Hardware Input & Output> <DAQmx> <Counter Measurements> <Period & Pulse Width>. The Example Finder has an information section that has information on the Description, Instructions for Running, Block Diagram Steps, and I/O Connections Overview. The last section will help with the connections. The input for the example titled Meas Pulse Width – Buffered –Cont.vi will be the gate of the counter specified in the “Counter(s)” control on the front panel … such as Dev1/Ctr0. So on your device the 6220, counter 0 gate is PFI 9 as you mentioned.
I understand that you are interested in getting started with the Test Panel in MAX first. The Test Panels are limited to Pulse Train Generation for counter output and Count Edges for counter input. Please use the Count Edges if you are interested in testing the device with a counter input task. However, the Count Edges will just be counting edges of the signal specified in “Edge Source”.
I also understand you are interested in using the internal clock from the 6220. The example I previously suggested uses a DAQmx Timing.vi to configure the duration of the task … for example finite or continuous. The Timing is set to implicit, since the signal wired into the gate of the counter is in fact controlling the timing. The source of the counter task for pulse width is the internal timebase when using DAQmx Timing (Implicit).
“Create a Counter Input channel to Pulse Width. It is important to set the Maximum and Minimum Values of your unknown pulse width as accurately as possible so the best internal timebase can be chosen to minimize measurement error. The default values specify a range that can be measured by the counter using the 20MhzTimebase.” - from the description of the Block Diagram notes on the example. I also link helpful KnowledgeBase below.
AE KB 2X6CMDDS: What Does Implicit Mean in the DAQmx Timing VI?
http://digital.ni.com/public.nsf/allkb/2B6477E3A9B7C07386256D1F0066FBDD?OpenDocument
Samantha
National Instruments
Applications Engineer

I am having data i want to measure pulse width without using hardware and tell me how to start and stop soft timer using labview

soft pulse width measurement

If you are creating a pulse in software somehow, then you can use Pulse Measurements.vi that's on the Analyze>Waveform Measurements palette. This will require that the input is of the waveform data type with signal and timing information. There's several timing functions on the time & Dialog palette that you could probably use. Check out Tick Count and Elapsed Time. If you could provide more details on what exactly you need to do, we could provide more help.

DAQmx Counter Input Measure a single pulse's pulse width

Trying to measure a single pulse's pulse width. It appears that the DAQ only makes the measurement on the read command instead of after starting the task. I just get a timeout error. Is there any way to arm to counter for measurement or am I better off making a seperate thread to trigger my single pulse?
double measured;
int numSamp;
TaskHandle taskHandle;
DAQmxCreateTask("", &taskHandle);
DAQmxCreateCIPulseWidthChan(taskHandle, "Dev1/ctr0", "", 0.025, 0.120, DAQmx_Val_Seconds, DAQmx_Val_Rising, "");
DAQmxSetChanAttribute(taskHandle, "", DAQmx_CI_PulseWidth_Term, "/Dev1/PFI10");
DAQmxStartTask(taskHandle);
//Trigger the single pulse here
DAQmxReadCounterF64(taskHandle, DAQmx_Val_Auto, 10.0, &measured, 1, &numSamp, NULL);
Thanks,
Dan

Which device are you using?
If you configure implicit timing (DAQmxCfgImplicitTiming) your measurements will be buffered and will begin when the task is started. The minimum buffer size is usually (always?) 2 samples, but that doesn't mean you have to read two samples back.
Best Regards,
John Passiak

Change pulse width in a continuous generation using an array of High/Low Times using NI-DAQmx

Hi,
I'm using a PCI 6259 (M-Series) Multifunction DAQ, and I want to use a counter to output a pulse train with changing low times. I want to use this output signal as an update clock, where values of Digital Output Channel, and the Analog Output channels updates to new values sequentially in the order specified in their repective 1D arrays in the front panel. I want the updates to happen at every rising edge of the clock pulse. The times when I want this update to happen are also user-specified by an 1D array of times in the front panel. So I'm trying to configure one couter to output this changing width pulse train.
I'm new to Labview/Ni DAQ. I'm using NI DAQmx, so far its been really nice and readable, and easy to understand. Even though I have never used NI-DAQ, I can clearly see that NI DAQmx is certainly much more programming friendly than NI-DAQ. I looked at the VI's available in the example, and also through many simlar posts in these Forums, and some web documents for my problem. Most of the solutions have focussed on changing times on the fly while the application is running. I want to specify the different times before a "DAQmx Start Task" is called. I'm wondering wether this is possible.
I was hoping I could store the pulse width values in a buffer, and the counter could keep outputing pulses with different widths in one continuous operation. The M-Series help file says that it is possible to do that "seamlessly", but I dont see yet how I can use the NI DAQmx to do that. Attatched is the part of the Help file where it says that.
Any help will be greatly appreciated.
Attachments:
Counter_Change_Frequency_Help.pdf ‏21 KB

Hi Kevin,
Thanks for your message. Well, I would like to point you to the 'DAQmx Timing' vi, which has an instance for change detection applications with digital input. I'm new to LAbview, but I'm wondering wether you can use that for your applications. Yes, I have seen the Viewpoint boards and their programs.. I have actually also looked into their Vi you are talking about, Kevin, for ideas to use with my board, but the core of the program is in C, which is something I would use as a last option, specially since I bought Labview to make life easier.
To get back to the subject of my post, their is a vi 'DAQmx Write", and one of its instance is 'Write Counter Single Channe SINGLE Sample', and there is no 'Multiple Sample" option available for writing counters, as is for the Digital Ports and Analog Outs. That seems to be a bit surprising. To refer the following example
http://zone.ni.com/devzone/conceptd.nsf/webmain/90DFE241E571056C86256FA4004ABB63
(pulse width modulation with NI-DAQmx)
If one can change values of pulse widths on the fly, I would assume thats it should also be possible to pre-define a sequence of pulse width values in a buffer from which the counter 'banks' can access the next pulse width from. ('Banks' are the 2 load register pairs for the counters and is described in the part of the M-series help file attatched in my earlier post).
Hopefully somebody from NI can address our problem. And yes Kevin, currently I have 2 options,... 1. to create a digital waveform before hand, which will use a large buffer ( I want an experiment to run for 1s, with 0.1us timebase, or
2. To use the example in the above web document and modify it a bit. Here frequency is changed on the fly, and a while loop checks if the frequency is changed in the at regular intervals. I could instead use a for loop to keep changing the frequency values, but I tend to think that the speed will be limited by software. I'm not sure .. I haven't tries that out yet.
Hopefully someone can send me a nice elegant solution.
Thanks.
Shomu

Pulse width modulated signals

Is it possible to generate a fixed frequency with variable duty cycle signals using counter/timer channels of my DAQ 700?
If yes, is there any example I could download?
If no, I am looking for a DAQ card that can handle
the job, I'd appreciate any recommendation.
Another part of my project is to read in a analog signal while generating this pulse width modulated
signal. So far I am not very lucky with one DAQ,
I am thinking of getting two. Does it sound overkill?
Please help.
Thanks

Could you provide a timing diagram for your digital signal?
I am a firm believer that a digital output device such as an NI timer can create any signal, given the proper software or hardware. I once did a high speed, gated, triggered data acquisition with only a single NI timer chip on the AT MIO 16E-1. It required about 75 feet of BNC cable, more PFI wires than you can imagine, four external logic devices (AND and OR, NAND and NOR boxes) all interconnected and basically tangled. I don't think I could repeat that setup without my documentation, but the point is, it worked.
The most important thing from that example is that I used a timing diagram. These are so vital in digital IO and timer applications that its not funny.
If you can't determine ho
w to do what you need from a timing diagram, just send me a copy, let me know what the basic specs are of the DAQ 700 (how many counters, interconnect capabilities, etc) and I can try to help.
Good luck.
As far as reading the analog signal at the same time...well, look at my example. I generated the trigger/gate signal with the card, and then read in the analog data (on several channels simultaneously.)

In Delayed Pulse Generation vi,Problem With THE PULSE WIDTH??

In Delayed Pulse Generation vi, I want to input a very low number for the Pulse Width while using an external timebase source. But the minimum pulse width has to be 2. Does anyone know how can I solve this problem??

Hey 45,
Unfortunately, there is no way to generate a pulse width smaller than 2x your external timebase.
There is an option to create a pulse of arbitrary width of your external source if you can afford some software processing in between. What you can do is use 1 counter to measure how many source edges of your card's internal timebase (80 MHz for TIO only, 20MHz or 100kHz for TIO and STC) your external signal is. This uses pulse width measurement as the counter application. Once you know how many source edges it takes to represent your pulse, then you can use triggered pulse generation and use the internal timebase with the pulse specs set to create the exact pulse width you want (and delay) and you can use your external pulse as the trigger. Th
is works well if your pulse is always the same width and you can measure it before hand. As an example, let's say your pulse is 20 internal timebase pulses when measured. This means you can use the pulse specs to specify a pulse width of 0.75 your pulse width by using only 15 internal timebase edges for your pulse width.
I don't know if I was clear above or not but if you give me your exact application you are looking to achieve, I might be able to help you out. Hope that helps.
Ron

Can I change the delay or pulse width on a trigered pulse on the fly in DAQmx

In the old DAQ driver you could not change the a triggered pulse delay or pulse width on the fly of a as there was a problem in the DAQ driver or was this a hardware problem?
Is this now possible with DAQmx , if not why not as you could do this with the old 16 bit cards in dos by updating the registers.
This has been a major problem with NI counters timers and one would have thought that by now this problem would be fixed.We need to do this with out stopping and restarting a task.
Any help here.
Ta
Colin

Hi Colin,
Please can you try the suggestion in this KB. hopefully it should still work with what you are doing. I can not find any information specifically on what you want to do with a triggered pulse. However this example program might give you some hints as well.
Regards
JamesC
NIUK and Ireland

External sample clock with pulse width measurement

Dear all,
I am using a NI 6220 board (programming with ANSI C) and would like to perform a "single pulse-width measurement" using an external gate signal and an external signal as source.
Using the "DAQmxCreateCIPulseWidthChan" command the program and card works only partly as intended. Namely, the external gate did work, but the card uses the internal 80 MHz time base signal instead of the external source connected to the default source pin (PFI 8).
I tried to route another PFI pin to the default source pin using the "DAQmxConnectTerms" command but this did not help either.
Obviously, I am missing something...
Best, Uli
Solved!
Go to Solution.

Hi Uli,
I posted to your thread here.
Best Regards,
John Passiak

Pulse width timing /demodulation

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