Digital output to switch external hardware

hello all
I am having trouble with error 200077 at a DAQ assistant. I am trying to output a signal of boolean values (skinny blue wire) but will not "go through" the DAQ board. I see a chart on the front panel that is constantly being updated throughout running the signal processing when the DAQ assistant is not wired into the vi. Initially I would just like to see that chart on an oscilloscope with relation to the original signal. Eventually, I want to trigger a mechanical ventilator with the signal. i'll post the vi, just in case that is helpfl to anyone.
thanks in advance,
pmn
Message Edited by BMEstudent on 08-04-2008 02:29 PM
Attachments:
Version_8_4_2008_DAQoutput.vi ‏381 KB

Hello pmn,
The loop iteration speed is however long it takes for all of the VIs in the loop to run. If you have a DAQmx Read in a loop, that VI is "blocking" until the specified number of samples are available in the buffer. If you specify 100 samples that VI will wait until they are available and then allow execution to continue. If you specify -1 samples the DAQmx Read VI will pull all of the available samples and continue execution immediately.
If you have additional analysis in series with the DAQmx Read the total loop iteration time will be the time to read + the analysis time. If you have a Wait (ms) VI in your loop it is a parallel process and the loop iteration will be the larger of the wait time and the code execution time.
With a simple acquisition, a majority of the loop time will be determined by the sample rate and the samples to read. I.e. if you sample at 1 kHz and read 100 samples each iteration, your average loop time has to be 0.1 seconds to avoid overflowing the buffer.
Cheers,
Brooks

Similar Messages

Can I disable 'digital output' and switch to internal speakers only?

Last month, a jack from a headphone broke off and got stuck in the audio input of my Macbook Pro.
They were able to get the broken peace out, but I think they damaged something in the input by pulling it out.
When I press the volume buttons I get this sign:
https://www.google.be/search?q=no+sound+mac&espv=210&es_sm=91&source=lnms&tbm=is ch&sa=X&ei=Ldr0UtnzNcb8ygPwwIHgAw&ved=0CAkQ_AUoAQ&biw=1020&bih=546#facrc=_&imgdi i=_&imgrc=o0nxcZoiz0kGUM%253A%3Bbd1IQ1bSgYnzxM%3Bhttp%253A%252F%252Fi54.tinypic. com%252Fop1amf.png%3Bhttp%253A%252F%252Fwww.mac-forums.com%252Fforums%252Fos-x-o perating-system%252F253164-no-sound-after-upgrading-itunes.html%3B211%3B205
When I go to audio preferences I only see 'Digital Output' as an option. (not 'internal speakers')
The Macbook still thinks there's a jack inside.
Is there a way to switch on to Internal Speakers (because they DO work, but I cant enable them) by disabling the Digital Output?

Are you seeing a red light at the port? It can get stuck so that it still thinks the headphones are plugged in. Try taking another headphone jack and plugging it in a few times.

Using mathscript to generate multiple digital outputs for switch control

Hello
I am new to this NI LV and a have kind of a basic question. I would like to use Mathscript to generate an array of bolean numbers which will be used to control the Digital I/O lines. I am using NI 6251 USB device and the Mathscript code runs well. But I have a problem using this array to control the Digital output. So I created a simple test programme where I set the DAQ assitant to generate 4 digital outputs(P0.0 ~ P0.3) and it gives error that ".. number of channels in the data does not match the number of channels in the task..." (see attachment) . How can I solve this problem thank you.
Attachments:
K-9.jpg ‏36 KB

looks like you did not initialize all 4 of the elements in the bool array....

USB-6009 Digital Output Current

You need to have all those grounds connected together - USB-6009 Digital Ground, ULN2003 GND, and the power supply ground. In this case it will not matter how they are connected. If they are not connected, then one of the devices could be damaged.
Lynn

Hi, I'm trying to increase the voltage of the digital outputs of USB-6009 device. I read a couple topics about using a relay but I could not manage it.
I was thinking to use 5V supply on the card since it has 200mA current on it, but when I use it with open-collector output, it can not switch the relay. When I measure the current between
5V and ground: 200mA,
5V and output, I read a value around 30-40 mA.
Why can't I use that 200mA with an output? This is the relay I'm using.
If this is not possible, can I use an external 5V supply (with more current) and a digital output to switch the relay without damage the 6009?

Controlling fpga digital output node from realtime boolean

I have a system where I want to turn on / off a digital output running on the FPGA.
Once I set the boolean on my realtime side (which turns on the FPGA output), I see the output turn on the CRIO, but it flickers on and off. (not latching?). I just want the FPGA to stay on as long as the output is turned on, on the realtime side. I cant change the mechanical action of the switch due to limitations on FPGA / RT according to labview ( I get an error at compile)
Any suggestions on how to correct this?
Solved!
Go to Solution.

I have simplified my program to something very basic to replicate the problem.
The digital output D0 switches on and off everytime the realtime loop cycles through.
If I run just the FPGA seperate and turn on the digital output control D0 it stays on solid. (until I turn it off again)
What am I doing wrong?
Attachments:
FPGA_RT_TEST.zip ‏144 KB

NIELVIS- digital output!

Hi was trying to work on some relays on the elvis prototype board, i see that the digital output give about 4.3V but for some reason the relays cant be activated by these, Could anybody pls tell me if that is because the digital outputs dont have enough current to activate the relay, or suggest anything to rectify this! I am currently trying to use those 8 digital outputs as switches to activate the realys.
Thank you
Rohith

Those specifications differ based on the internal DAQ board you are
using in conjunction with the ELVIS unit. The ELVIS uses either
the 6036E or the 6251, there is no way to change the actual output
voltage of the digital lines, they only output the specific state
either high or low. The NI-ELVIS User's Guide has more information about the specific specifications of the NI ELVIS.
Good luck!
Micaela N
National Instruments

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
I want to switch on one output line0 and after a delay 5sec switch on line1 output and after a delay of 3sec switch on line2 output and sense input line 0 and line 1 .
How can we know the status of output ie output is on or off.
Since i am using the IO card for first time suggest me in this.

Hi
I am going to assume that you are using LabVIEW 7.1 for this application. If you are trying to acquire data from an external device after outputting data to that device, the DAQmx tristate property node will give you this functionality.
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

While dealing with an external hardware i got a Java update4 request,but was not able to complete that update.After that when i switch on my Mac it shows reinstallation required.i was working with OSX 10.8.5,but after reinstallation now it is 10.7.5 .

While dealing with an external hardware i got a Java update4 request,but was not able to complete that update.After that when i switch on my Mac it shows reinstallation required.i was working with OSX 10.8.5,but after reinstallation now it is 10.7.5 .And while doing search for update it shows your software is uptodate..

Hi Hal,
One possibility, is a strange occurence when applying the big 10.5.8 combo, most people have to Repair Permissions twice in a row, then reboot.

Externally Triggered 6534E Digital Output

Hi Dear Friends,
I have get a question on how to do the triggered output for the 6534E card. Right now I am using the 6534E card to output a digital gate pulse, and I want to synchronize the output of this gate pulse to an external source, which is the Sync output of a Angilent 33220A function generator(10 kHz). I want the rising edge of one trigger pulse(the sync output) to start one digital gate pulse output, and when one digital gate pulse if finished it waits for another rising edge of the trigger pulse to start another digital gate pulse.
For the more detailed description, please have a look at the attached waveform. Hope you can shed some light on the possibility of doing this.
Thanks a lot for the help.
Attachments:
6534 Triggered Digital Output.JPG ‏95 KB

Hello tiddlycorona,
From the diagram you provided, you can try the Gen Dig Pulse-Retriggerable.vi. This LabVIEW example demonstrates how to generate a digital pulse from a Counter Output Channel on a digital trigger. The Initial Delay, High Time, Low Time, and Idle State are all configurable. It also shows how to use a Digital Start trigger, so the digital pulse is not started until a trigger signal is received. Though the pulse is configured in terms of ticks, it can easily be modified to generate a pulse in terms of Frequency/Duty Cycle or Time.
Best regards,
Ali M
Applications Engineer
National Instruments
www.ni.com/support

How to set a digital output using a switch on the operator interface?

Hi, is it possible to set a digital output using a switch on the operator interface?
Thanks,
Mike

Unfortunately, no. It is on our hit list...
This account is no longer active. Contact ShadesOfGray for current posts and information.

How do I calculate 'uptime' of a digital output

Hi everybody,
I'm new to these forums and I am currently evaluating Labview for a series of lab tests where we measure energy balance in a chemical reaction. I've already
I have a USB 6008 wired to a relay drive (thanks to these forums) and a heating element and I want to measure the total time heating element is 'on' during 24 hours to calculate the energy the system is getting. The heating element switches on and off based on the signal of a thermocouple. Is there an easy way to measure the seconds that the output port wire to the heating element is active? Device-independent would be preferable (like measuring the signal uptime of the input of the digital output of the USB6008)
I tried a lot of options today, like while loops, sequences, case structures following several postings here but all of them failed miserably - while the problem sounds so easy. I could easily do it in the hardware by wiring the output of the relay drive to a bauser timer, but that would be giving up too soon
Any help would be appreciated.
Best regards,
Dimitri

Hi Dimitri,
Welcome to the NI Forums! It's good to hear that you've already received some help here.
Q: Is there an easy way to measure the seconds that the output port wire to the heating element is active?
A: Yes! The method we can use to perform this action depends on the sort of architecture that you're using at the moment, however we can take advantage of the section of your code which defines whether the line should be on or off. When it's on, using a While Loop we can use a Timestamp to keep track of the current System clock; this Timestamp will update on every loop iteration. If we use a reference Timestamp which is created outside of the While Loop when we first begin to drive the line high, we can simply work out the difference between the current Timestamp and the reference Timestamp to get the total time.
This kind of code will also be device independant because it relies only on the computer it is used on.
I hope this helps!
Alex Thomas, University of Manchester School of EEE LabVIEW Ambassador (CLAD)

No digital output

All of a sudden the Digital Output on my iMac has stopped working. There is no red light coming out of the toslink cable. In System Preferences/Sound there is no Digital Out in sound output devices anymore. I have checked that the cable is ok.
Previously the system switched over from internal speaksers to digital output automatically when inserting the toslink cable but now nothing is happening except that the sound is vanishing.
Is this a hardware error? The iMac is just 3 months old so I sincerely hope not.
Thanks for all tips&tricks I can get.
Regards

Hi,
Generally speaking, An Audio Device do need more driver besides USB driver to make itself work properly. In terms of your situation, USB driver is not enough to make your Audio Device works properly. I think S.Sengupta
is right. Actually it would be better to contact Digitrack support to confirm its product compatibility with Windows 7.
Roger Lu
TechNet Community Support

Digital output daq

Hi,
This should be very easy, but for some reason I'm having issues. All I want to do is have a switch control a digital output. I am using an NI 9742 Dsub (link) card, which should be capable of digital output.
Attached is my code, with a simulated card. When testing I switch the DAQ assistant properties to the real card.
Using this code, I cannot get a DC output at all, my scope just hovers around 100mV. Using other cards, I have the Analog I/O working just fine, but for some reason the digital output on this card isn't? Also, if you look at the card, there are 8 green LEDs towards the top. I believe each one specifies when an output is on. When I turn the switch on, the corresponding light does in fact light up, but I cannot measure a voltage? Is there some setting I'm missing?
Hopefully this makes sense. Thanks!
-secondary question: Once this works, how do I change the output range. The specs say 6V-30V output, but I do not see where to change this.
Solved!
Go to Solution.
Attachments:
digital output help.vi ‏42 KB

If you dig into the Operating Instructions, you'll notice that you have to supply an external power supply. The way this card works to by connecting the external supply to the output. You should also see this on the side of the module. NI's site doesn't have a good sideways shot, but it looks like a switch.
So basically, with no power supply you will get no voltage out. The output range is also adjusted by adjusting the external supply.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Power-On state of digital outputs in 6713 card

The card manual says Power-on state of DIO is Input(high-Z). However after I power up the computer before I ryn my software, I measure DIO outputs as high TTL voltage(about +5V). Similar situation happens with GPCTR0_OUT which I use for a pulse train. Again before any configuration when I expect low TTL output, the high level comes up. When I run my software I have all this configured properly. But this unexpected power-on status does not look right , also it is not compatible with my external hardware and makes it possible damage.

The default state for the DIO and counter out lines is a internal 50 kOhm resistor pulled up to 5V. This is listed in the user manuals. However, you can change the default state of any of these lines by adding a external pull-down resistor. Here is a KB that discusses this in more detail.
http://digital.ni.com/public.nsf/websearch/008995633E33E47486256B5F00034436?OpenDocument
I hope this helps.
Joshua

How to combine Digital Output, a delay and Analog Input in a fast loop

I need to develop a process loop that runs at least at 250 Hz that performs a Digital output, than a delay of 50 microseconds and than an analog input of all the channels. All will be done using ATI MIO 64E3 card. Of course, the acquired data will be processed, displayed and saved. The loop will be running for several minutes until user stops it.

The fastest and most precise timing will occur if you use hardware timing. You can apply hardware timing to analog input on the E Series boards, but not the digital lines. Let's focus on the analog input first. Continuous waveform scanning uses a scan clock, which can be the board's internal one or an external one which you apply. If you want to scan all the channels 50 microseconds after a digital rising edge, then you need an external signal to signify that scan clock.
The E Series boards also have 2 counter/timers onboard that you can use for this purpose. You can set up a retriggerable pulse generation operation, where the counter receives a trigger and then on the user specifications, produces a pulse. You can have that route to the analog input scan clock.
The trigger signal for the counter is that digital pulse. As I mentioned earlier, there is no hardware timing for the digital lines on an E Series board. We do have other digital boards (653x family) that have hardware timed operations if precision is important. If you are satisfied with software's resolution (in the milliseconds), then you can call the E Series board digital function in a loop with a software timer. That digital line can route to the counter to act as the trigger.
So, on the programming side, you can have three separate and independent operations in parallel. One is for the digital function to output on that line every so often. Another is for the counter set at the retriggerable pulse generation. The last is for the analog input. I will describe this in terms of LabVIEW, but it can be done in a similar fashion with the NI-DAQ function calls or Measurement Studio.
The digital examples are in the LabVIEW >> Examples >> Daq >> Digital >> E-Series directory. The Generate Retriggerable Pulse example is in the LabVIEW >> Examples >> Daq >> Counters >> DAQ-STC directory. The E Series boards use the DAQ-STC timing chip.
Go to the LabVIEW >> Examples >> Daq >> anlogin >> strmdisk.llb directory and start with the Cont Acq to Spreadsheet File. This shows how to continuously acquire data and stream it to disk while displaying the data on a chart. Streaming to disk is the efficient way to save data while you are acquiring, as it eliminates the overhead of always opening and closing the file through the iterations of the loop. This saves to a file that can be opened by other applications (Excel, Word, etc.), but it is not as fast as writing to a binary file, which must be opened and read back through LabVIEW. However, for your ~250 Hz rate, it should be fine. Then, go to the LabVIEW >> Examples >> Daq >> anlogin >> anlogin.llb and look at the Acquire N Scans -ExtScanClk example. This shows how to apply the scan clock. Here, the AI Start that you saw in the previous example is replaced by 4 VIs (3 AI Clock Config's and the AI Control). Make those changes to the first example and then add a constant 0 to the AI Control parameter for total scans to acquire. That specifies the continuous operation. The File >> VI Properties >> Documentation menu item of the example describes the physical connections.
If you aren't using LabVIEW, use the NI-DAQ User Manual and the NI-DAQ Help file installed on your machine. You can look at your AT E Series User Manual at the http://www.ni.com/manuals pages for more information on the hardware. Also, if you want to route those signals internally on the board, you can find some entries in the KnowledgeBase at the http://www.ni.com/support pages.
Regards,
Geneva L.
Applications Engineering
National Instruments
http://www.ni.com/ask

Digital output to switch external hardware

Similar Messages

Maybe you are looking for