Outputting analog w/DAQ at different times?

I have a dual-output DAQ (NI-6120) and I would like to output data on each channel as soon as it is ready. Right now, using the DAQ Assistant block, I have to use a merge before the input which causes the DAQ block to not to generate the analog until both signals have arrived. With the below, I would expect to see a phase shift on my scope, but I don't.
Thanks!
Ben

The below pseudo-code is almost exactly I need (except for the not-working part!) Like I said, the problem is the merge waits for both signals to get there before passing them both to the analog output. Seems like the solution would be to use two analog output blocks, one for each signal input. But it won't let me do for the same hardware device.

Similar Messages

How to read from DAQ in different time intervals

Hello,
I am currently using LabVIEW 2010. I am new to LabView.
I have 9 thermocouples I want to record the temperature from and create a graph.
For one graph I want to graph the data every second for the duration of about 1.25 hours. For the other I want to record and graph the data every 2 minutes for a duration of 30 minutes. The temperature then would be ramped up in an oven and set to a higher temperature. When it is stabilized, recording of the data again will begin again at intervals of 2 minutes for the duration of 30 minutes.
The first is only to see the real time temperature variation while the program is recording and running. The second graph and data is what I will use to analyze.
What I need help in is finding out how you can read from the DAQmx at two different time intervals. I tried two parallel loops with each one graphing the two separate graphs I need with a delay time. Those two parallel loops where then surrounded by another while loop. The result is that the outside loop waits until both loops are finished so I do not get the correct results for the real time data graph.
Is there a way to call on the DAQ data you need at the time interval you desire? Any suggestions to solve this problem? Thank you for your time and help.

You are on the right track. Sample the data at the fastest rate and send it to the 1st graph. For the slower graph, take a sample from the faster data at your desired time interval. You could use a timer and a case structure for something quick and easy and still have everything run in the same loop. You could use two loops running at different speeds, it is just a little more involved and a few other things to consider.

I want to have two different operations on two analog output terminals of DAQ. When I work

with AO0, it works. But after I add in another channel, AO1, there is an error saying that 'specified group is in use'. Actually, I assigned different group number for AO0 and AO1 when configuing the device using AO Config.vi. How to deal with this error?I want to have two different operations on two analog output terminals of DAQ. When I work with AO0, it works. But after I add in another channel, AO1, there is an error saying that 'specified group is in use'. Actually, I assigned different group number for AO0 and AO1 when configuing the device using AO Config.vi. How to deal with this error?

with AO0, it works. But after I add in another channel, AO1, there is an error saying that 'specified group is in use'. Actually, I assigned different group number for AO0 and AO1 when configuing the device using AO Config.vi. How to deal with this error?Hey Steve,
Doug is correct. Both analog outputs have a shared clock. If you want to write to both outputs simultaneously, you will need to include both of them in the same operation (group).
You can write a 2-D array to the AO Write VI in which you can include data for both channels. In the 2-D array, column 1 will be for the first channel in the channel list and column 2 will be for the second channel.
I hope this helps.
Regards,
Todd D.
NI Applications Engineer

DC pulse output analog input

I am using a 6221 PCI DAQ card and attempting to put out a DC level for a several different times. During the output of each DC level I need to sample two DC inputs via the analog input. Most of my DC levels last for 100s of seconds each and a sample rate of 1S/s on the analog inputs is OK.
My problem arises when I attempt to place a 30ms pulse into the analog output. During this 30ms I need to increase the data rate of the analog input.
I have attempted to use a while loop to control the time between changes but can not get the sampling rates correct to allow for the correct number of samples.
On suggestion has been to take all data at a fast rate. The test will last in excess of 3000 seconds and I get way too much data at a fast rate.
I need to be able to change data rates on the fly as I change the DC levels.
Does any one have any ideas?
Thanks,

John@Saft wrote:
I know when the pulse is to arrive before it happens. I have an array of data including voltage outputs, duration of output, and what data rate to sample at.
My problem is insuring the sampling starts before the pulse arrives and continues for the duration of the pulse.
One way I'm sure can work uses "Continuous Acquisition. "See: "Cont Acq&Graph Voltage-Analog SW Trigger.vi" example.
If the DAQ-rate is known before leading-edge of pulse, then, start the Acquisition at whatever frequency's needed, making the input buffer bigger than required, then when the end-of-pulse arrives, reach-into the input buffer and pull-out the "pulse". With a little work you may find an example that uses a "stop-trigger"
There may be a "slick" way to do this without "Continuous Acquisition" using a parameter called "Pre-trigger" scans. My first LV project (circa- 1990) used this, and I've done it with at least one "E"-series board, but not yet under DAQ-MX - and couldn't find an example with Internal clock, External Trigger.
Cheers!
"Inside every large program is a small program struggling to get out." (attributed to Tony Hoare)

Problem in updating value at different time interval

Hello,
Can anyonce suggest me how to update different value at different time interval.
I want to use only one while loop but I should be able to send data at different rate.
Eg:- I have 3 input ,10,20,30
I need to give output 10 at every 5 ms
20 at every 10th sec
30th at every 13th sec.
so my output should be
10 at 5th sec
10 at 10 sec
20 at 10th sec
30th at 13th sec.
Please let me know if anyone has solution for it.

Is this under windows on in a realtime system?
In the varous posts, you are sometimes talking about milliseconds, sometimes about seconds
You could run a timed loop at 5ms time and use quotient and remainder for each multiple with three parallel case structures.
Here's a possible solution for the case:
output 10 at every 5 ms
20 at every 10th sec
30th at every 13th sec.
as in the original post...
LabVIEW Champion . Do more with less code and in less time .
Attachments:
VariousTimes.png ‏8 KB

Simultaneous serial and analog input DAQ?

Need to sample from the serial port and 4 channels
of analog input at the same time. Figured I need
to use an internal clock to sync the aquisition
since the serial port response delays every so
often. Does anyone know how to sample from an I/O
port and a DAQ card at a consistent sampling
frequency in LV? Any help would be greatly
appreciated.
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

[email protected] wrote:
>
> Need to sample from the serial port and 4 channels
> of analog input at the same time. Figured I need
> to use an internal clock to sync the aquisition
> since the serial port response delays every so
> often. Does anyone know how to sample from an I/O
> port and a DAQ card at a consistent sampling
> frequency in LV? Any help would be greatly
> appreciated.
You don't mention what kind of data rates you are talking about. I have
put together several systems that combine time-stamped serial and daq
channels, but in all cases, the serial data was running at around 1 Hz.
The daq channels were often running much faster (100Hz to 1KHz). If
your channels fit this description, then it is possible to synchronize
your data (more or less)
. You can use software timing to set up the
slow loop and acquire the serial data, and used buffered A/D to read in
the appropriate daq channels. The synchronization isn't perfect, but
may be "good enough".
Best of luck,
Dave Thomson
David Thomson 303-499-1973 (voice and fax)
Original Code Consulting [email protected]
National Instruments Alliance Program Member
Research Scientist 303-497-3470 (voice)
NOAA Aeronomy Laboratory 303-497-5373 (fax)
Boulder, Colorado [email protected]

I recently purchased FaceTime from the Application Store. After approx. ±10 meg, the application resets and starts downloading again. I have tried to download it at different times of the day but with the same results. I have been in contact with Apple su

I recently purchased FaceTime from the Application Store. After approx. ±10 meg, the application resets and starts downloading again. I have tried to download it at different times of the day but with the same results. I have been in contact with Apple support and have tried different options with the same result. I cannot download a new Version because in my Purchased List the applicaiton (FaceTime) is still there, and because I have halted it it tells me to resume. I can’t, because the same thing is going to happen. I have tried all the various troubleshooting tips supplied by my ISP and also Apple Support with no luck. I am currently working on a IMac OS 10.6.7. Has anybody got any ideas? Any suggestion would help. Thanks

Amol Soni wrote:
As I said, I tried everything what the manual says, but hard luck. I have taken an appointment for today, lets see what happens.
Also there is no activity on unit when I use the remote. The unit is stuck on the first page itself where we have to choose the language. The unit seems to be fine to me but the real problem is remote does'nt have activity. The IR is not responding while pressing any of the button.
Good luck with your appointment.
Not much consolation but even new products can have issues and might need a trip to a store to return/replace.
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AC

I would like to know how can I set songs in iTunes to play at different times automatically during the day. i.e. one song at 10am the other at 10:30am etc..

I would like to know how can I set songs in iTunes to play at different times automatically during the day. i.e. one song at 10am the other at 10:30am etc..

How can I save my data and the date,the time into the same file when I run this VI at different times?

I use a translation stage for the experiment.For each user in the lab the stage position (to start an experiment) is different.I defined one end of the stage as zero. I want to save the position , date and time of the stage with respect to zero.I want all these in one file, nd everytime I run it it should save to the same file, like this:
2/12/03 16:04 13567
2/13/03 10:15 35678
So I will track the position from day to day.If naybody helps, I appreciate it.Thanks.

evolution wrote in message news:<[email protected]>...
> How can I save my data and the date,the time into the same file when
> I run this VI at different times?
>
> I use a translation stage for the experiment.For each user in the lab
> the stage position (to start an experiment) is different.I defined one
> end of the stage as zero. I want to save the position , date and time
> of the stage with respect to zero.I want all these in one file, nd
> everytime I run it it should save to the same file, like this:
> 2/12/03 16:04 13567
> 2/13/03 10:15 35678
>
> So I will track the position from day to day.If naybody helps, I
> appreciate it.Thanks.
Hi,
I know the function "write to spreadsheet file.vi"
can append the data
to file. You can use the "concatenate strings" to display the date,
time as well as data... Hope this help.
Regards,
celery

Some, but not all, podcasts existing on the iPod no longer appear in iTunes. Different podcasts have been affected at different times, after changes in the state of the iPod. Only podcasts are affected.

I have not seen this precise issue addressed anywhere. I don’t know if it’s an iTunes or an iPod problem:
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this, after normal behavior for more than a year since purchase of the iPod.
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- Only podcasts are affected.
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I’d begun syncing an iPhone via iTunes.
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I ultimately reset the iPod and manually resynced all the podcasts I currently had on iTunes. That worked, though I had to painstakingly add in all the other content deleted by the reset.
So: after that reset and manual sync, all podcasts and episodes on the iPod were visible to iTunes and I was able to delete the podcast and its — now 18 — episodes I’d wanted to get rid of to begin with. But the next time I connected the iPod, only 8 podcast episodes out of 21 episodes total existing on the iPod were visible to iTunes. These are different podcasts; I’d deleted the original “invisible” ones.
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I have the same problem- i see my movies in the ipod section in itunes and they even show as mpeg4 in the 'kind' section but they dont have that small TV icon next to them. if i play these in itunes, they play fine- but try playing them on the ipod and all you hear is the sound and no picture. All videos that i manually transfer work fine in the beginning- its when i hook up the ipod to the comp again and start itunes- they start showing up without the 'tv' icon!! i have to again transfer them from the itunes library to activate them as videos.
Need Help!!!

How to make the counter count or start at different time

Hi,
How to let the counter count the time, that doesn't start at the same time ?
This timing system is a sport timing system for canoe competition, it need to track 6 competitor that start at different time .
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Solved!
Go to Solution.
Attachments:
multi competitor.zip ‏50 KB

HI,
ya, i run it. I mean i know how to make it to 6 competitor already , and yes, it works but the time, it still count or start at the same time. I need to run each competitor at different time , like this competitor A 20-2-2012.VI . This is the one i do but it cant put a stop button. once i put a stop button, the clock stop counting but the whole VI is running.
Regadrs,
Sam
Attachments:
competitor A 20-2-2012.vi ‏139 KB
3switch 3-2-2012.vi ‏14 KB

How to create an event in two different time zones?

Hello,
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Hi Alex,
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Write arrays into a text file in different columns at different times

Hi,
I have a problem write data into a text file. I want to write 4 1D arrays into a text file. The problem is that I need to write it at different time and in different column (in other word, not only append the arrays).
Do you have an idea to solve my problem?
Thank you

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read file into 2D array
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LabVIEW Champion . Do more with less code and in less time .

How to display different Time Statement forms in ITS service PZ04

Hi all,
I am working on a underlyinge R/3 4.7 system and are working with standalone ITS and ESS 50.4. I am posting this question to find out if any of you has experience with my problem.
The business wishes to use the ITS transation PZ04 standard and wish to be able to display different Time Statement forms in the transaction through customized variants for the report(RPTEDT00) that the PZ04 transaction executes. In the IMG it is posted that one variant has to be created called HRESS_TEDT00 and this works, but restricts the PZ04 transaction to always be called with this variant and therebye the same Time Statement form every time.
I then by debugging found that the underlying ABAP code processed from SAP standard has a variable VARIANT that is hardcode to = HRESS_TEDT00.
The question is: Is there anyway to setup the PZ04 transaction so that it can be dynamic decided which variant should be used, f.ex. from persons subarea from infotype 0001?
Looking forward to here if anybody can help.
Regards,
Allan Brauer

hi allan,
cud u plz help me how to sort out this problem actually in mu company the same scenario is here need to be display pe51 form instead of standard hrforms.....
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I have "chatted" with customer service 5 different times. I was sent here. I have activated Photoshop Elements 9 on two different iMacs. They are both dead and I am unable to get it to activate on my newest computer. iMac. Can anybody help me?

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Outputting analog w/DAQ at different times?

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