Pulse ON/OFF - digital outputs

I have this application where I need to turn ON a digital output for like 50ms or 100ms and turn it OFF. I call it Pulse COntrol
Here is an attachment jpg that shows how I am achieving it.
Another question if I may regarding loop timing. I have a while loop which iterates at 100ms. I choose a certain part of the program and make it a Subvi to clean the program to look more readable. Will the program still run at 100ms per iteration? For example, I have an equation that calculates a valuve from a analog input. To make the program clearer, I put the calculation into a subvi and send info and receive info through subvi panes. Will this affect the loop timing? I hope my question is clearer.
My program does a lot more than just calculate a value, hence wondering. THANKS!
vj
I may not be perfect, but I'm all I got!
Attachments:
p.JPG ‏22 KB

hey VeeJay,
did you want suggestions for how to do your Pule Control a different way, or were you satisfied with the way you have it implemented in the code you sent a pdf of? thanks!
~kgarrett
Applications Engineer
National Instruments

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Turn off digital output?

In the back of my Mac Pro I see a red light above the audio jack. I cannot hear audio. In audio control panal it says for output "Built in digital output" How do I shut this off and back to analog? I know on my MBP I stick a paper clip into jack and it shuts it down.

If you use a paper clip in a macbook pro, you'll want to use a coathanger for a Mac Pro.
But a better solution would be to enable the line out or internal speakers in the Sound Preferences Panel. If you don't have any option besides Digital Out, then you have a hardware or software issue that you can't fix with a paper clip, and the first thing to do would be to reset the PRAM.

USB-6009 pulse train generation with digital output....

Hello!
I've bought a new USB NI-Card (USB-6009) and now I'm trying to adopt an old vi that uses traditional DAQ drivers. I wrote that vi for a PCI NI-Card (PCI-6024E), which has two counters to generate two pulse trains simultaneously. Now I've only one counter and that's why I'm searching for a good way to create pulse trains using a digital output! The pulse trains are both ranging between 100 Hz and 100 kHz.
I'm sure somebody has an idea how I can solve the probem in the best way
Kind regards,
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You can't do it with this low cost board. Both digital and analog outputs are software timed only. The analog out is rated at only 150 samples/sec and the digital is about the same. You can't even use one of the counters because it is not a hardware timed counter output. It is an event counter only as an input.

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
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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.
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Unwanted 5VDC (uS) Pulses on DAQCARD-1200 Digital Outputs

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These blips can occur when writing to a digital port, and not masking the bits you do not wish to change.
If these blips are causing problems, take a look at the Write to Digital Port.VI. Double click on its icon to open its front panel. Go to its block diagram. You'll see where the port is configured on iteration 0, and then the Port Write is called, and there is an input to mask lines. This is what you'll need to do--put a value on this input to mask lines you want to remain the same. This should fix the blips you are seeing.
Also, if you are not manipulating more than one digital line at a time, you could use the Write to Digital Line.VI, which would accomplish the same thing. But if you need to update more than one line at the exact same ti
me, this method won't work for you.
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Trigger digital output at every 10 digital pulses

How can i generate an output pulse at every 10 input pulses comming from an encoder?
I need to trigger a sensor at every 10 encoder pulses to get data from the sensor.

Hello jyp777,
What you will need is a counter with an if statement that activates a digital output every 10 ticks. To do this, I would look at a LabVIEW example titled: Counter - Count Edges (Continuous Clock) that can be found under Help >> Find Examples... >> Hardware Input and Output >> DAQmx >> Counter Input in LabVIEW. Using this example VI, it should be a simple step to add a condition that triggers a digital output when the count reaches 10.
You can also use a Digital Output example if you need help in this area. These examples can be found by going to :
Help >> Find Examples... >> Hardware Input and Output >> DAQmx >>Digital Output. I would recommend "Digital - Continuous Output.vi".
Happy LabVIEW coding!
Thanks,
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Applications Engineer
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Digital stimulus-frequency response: Need to drive with digital output trigger. Using counters for response.

I need to drive stimulus-response with a software driven digital trigger and NI-TIO counter based response. No analog I/O is really relevant, although I have a PCI-6035E multi-function DAQ as part of my gear. I intend to use the analog, but its timing is non-critical and can be software timed.
The real trick is that I want to set the basic timing of the system (in the range of 1 - 50Hz) from the timer0 on the 6035E. This signal needs to be replicated to drive a trigger pulse and to route through RTSI (or a PFI) to trigger frequency counts using the four possible groups of counter/timers on the 6602.
What I need is:
while( enabled )
Repeat at (
software controllable rate = 1-50Hz)
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same trigger sets an RTSI line
- Software Set Delay (usually zero)- stable is more important than the delay time!
Count for software set time on 4 counters
analog samples
Post-process
I want to do this in LabView. I have checked out the Advanced sychronization demos online, but the examples all use analog triggering and buffered digital I/O. This doesn't really address what I need to do.
I have made some failed attempts which relied on software to sync up the trigger and the response frequency acquisition. This is definately flawed. I need to start the counting right after setting the digital output trigger, and stop the count after a fixed interval for frequency calculation.
I am having trouble working through the signal routing to get the timing to trigger off the digital stimulus output pulse.
Any help would be appreciated
Thanks,
Joe

Joe
What are you using the trigger from the 6035E for? I do not know what you mean by, "to trigger frequency countes."
If you are having problems just routing the signal to the 6602, here is a vi that shows you how to route a signal through the RTSI cable to use as the source of a counter.
Brian
Attachments:
Route_RTSI_to_Source.vi ‏67 KB

PCI-6023E & digital output

Hello,
I have a PCI-6023E and I want to generate a continous pulse train with a digital output line, and I need to know the maximum frequency for this pulse train that I can generate.
Thanks a lot for your answer.
Regards, Anacelia

Hi Anacelia,
You should not realy on this answer without verifying with NI first. So here goes.
Page 347 of the catalog indicates the supported data transfer mode is "programed I/O". This indicates that each line state change must be initiated by an operation of the controlling software. Therefore, the upper frequency limit is determined by how often the code that sets or resets the line runs.
So, the upper limit is determined by the software and the environment it is running in. If you are woring in Windows environment, and your machine is faster than about 400 Mhz then there are two factors to concider when answering your question. How fast does the code run, and how deterministic is it.
If determinism is not an issue, you could resonably expect to get
about one update every 10ms if the code is clean. This would give you 100 update per second or about 50Hz.
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Like I said, verify what I have said with NI.
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Ben Rayner
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Simple digital output

How can i use counter as simple digital output(On, OFF) for 6602?
I want to use counter output (PFI_32) as simple On/Off output, because in the future
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Hi,
An example of writing to a digital output line can be found at:
C:\Program Files\National Instruments\NI-DAQ\Examples\VisualC\Do\DOoneline.C
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DIO_28 of TIO board. DIO_28 is pin 32.
I hope this helps, and have a Great Day!
George

Solution to my Audigy 4 Digital Output probs... please make a stic

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Athlon 64 X2 5000+ BE
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I[color="#ff0000"] unplugged the power to my speakers, and reconnected everything. As soon as the power was back up, the sound started playing (I had a .MP3 on for testing).
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2. Apparently, some situations introduce a faulty signal to the digital output that scrambles the speaker units and they refuse to operate any longer.
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Please please please!
Make this a sticky for future me!!!

The Digital output jack on the card isn't of optical signal type.....you will need to get those I/O module mention bt johnston2 for optical connection.

How to give delay in switch on digital output lines

Hello All,
I am working on PCI-6514 Digital IO card, I am writing a sequence to my application using DAQmax for Digital input and output lines
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Hi
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You will then need a DAQmx write.vi to output your digital data followed by a DAQmx channel property node. Select Digital Output>>Tristate on the property node and wire a true constant into it. After the property node, you can use a DAQmx read.vi to read the data coming into the digital lines. By using the tristate property node, you can avoid stopping the digital output task and starting an entirely new task. I am attaching an example program that will demonstrate this.
Regards,
Hal L.
Attachments:
digital input and output.vi ‏39 KB

How do I calculate 'uptime' of a digital output

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Dimitri

Hi Dimitri,
Welcome to the NI Forums! It's good to hear that you've already received some help here.
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Alex Thomas, University of Manchester School of EEE LabVIEW Ambassador (CLAD)

How to do a digital output triggered by the falling edge of a clock?

Hello !
I would like to do a digital output (on a given line of a pci 6602 card) triggered by the falling edge of a clock.
More precisely, a pulse train is generated. I have to output each bit of a variable (first, the LSB ; then, the others bits, until the MSB), each bit being transfered on a falling edge of the pulse train. How could I do that, please ?
Thank you for helping me.
Julian.

see the following link (other forum same subject)
http://forums.ni.com/ni/board/message?board.id=40&message.id=1634

Problem with digital output and microph

Hello! I recently bought a new motherboard MSI K8N SLI Platinum that have onboard Sounblaster Li've 24bit, with coaxial and spdif and also the standard outputs. I ve connected via a fiber optical cable to my amplifier and i checked the digital output only box to the advanced settings on the mixer. I am hearing sound very well from my amplifier but when i connect headphones to with microphone to my soundcard , i don't hear anything at all from my headphones. Also i cannot speak via microphone. If i uncheck the box digital output only i hear sound from my headphones and also i can speak to microphone. Is there some way to have them both enabled? In my previous motherboard i didn't have that problem. I could hear sound from my amplifier with pcm signal and from my headphones and microphone analog at the same time.
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Thibaud,
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Lynn

How to use Digital output to turn on sensor for Analog Input?

I am trying to use a digital output to turn on an array of sensors that I then wish to read on 16 analog input lines. I have a 6024E DAQ card. I am planning to take data at 10-20 hz, so not terribly fast, but I will be acquiring for long periods of time (days) so I will be streaming data to disk.
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, write the data to disk and get back to the starting point... perhaps this is so fast that I don't need to worry about it? The actual timing of the samples (be it 10 or 20 hz) isn't too critical, as long as I can record at what time they were taken... it would be frustrating to find that I was several seconds off after days of data.

Hello,
Thank you for contacting National Instruments.
If you are worried about the time of your acquisition being off, then you should associate each voltage measurement with a timestamp. This will allow you to know the exact time at which the sample was taken and you will never be off. You can use the Get Date/Time in Seconds.vi in our while loop with your AI code so that you can read a sample and read the time. You can than log the voltage value and the timestamp to your file.
Regards,
Bill B
Applications Engineer
National Instruments

Pulse ON/OFF - digital outputs

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