Combine Analog outputs for higher current drive

I'm using a cRIO 9263 analog output module. The current output specification is 1 mA. If I need 1.2 mA of current, can I use two outputs in parallel?
SteveA
CLD
FPGA/RT/PDA/TP/DSC

I am not familiar with that device, but, in general when paralleling voltage output devices which were not specifically designed to be paralleled you need to include some ballast resistors. They allow for slight differences in the output voltages of the two (or more) devices and promote current sharing.
Put one resistor in series with each output. Connect the other ends of the resistors together and connect this to the load. The value of the resistors depends on the amount of current, the voltage difference between the two outputs when given the same digital code, how much voltage drop in the resistors can be allowed, and perhaps other factors such as how fast the output must change.
I can help with the calculations if you are not familiar with them, but I will need more information about the voltages and loads.
Lynn

Similar Messages

Do we have Digital to Analog converter with high current output?

Do we have Digital to Analog converter with high current output? I need 8 channels and each channel has at least 100mA current output.Thanks!

I have never heard of such a device. You will probably need to follow the D/A with an amplifer for each channel.
What is the voltage range and speed required? Any special protection requirements (such as current limiting)?
Lynn

Analog outputs for Blu-ray players

I'm not even sure if you can play a Blu-ray on an analog TV, but the internet features are usable, if you could display them. I know HDMI to RCA adapters can be purchased, but why make the consumer have to buy them. MANY people still have analog televisions. I think a large market is being missed. I use my Blu-ray players for the internet functions a lot more than I play discs.Also, many people still have analog stereos and can't output the sound. I know some players have coaxial outputs, but older stereos can't use them.It's going to be a long time before everyone has digital TV's and stereos. If these units had RCA video and audio, they could still have use for a Blu-ray player.

Hi
I saw your question and was wondering if 4 months later you had found out any useful information about the BDP-S780 connectivity to any TV. Info about the webcam/video camera to connect to it would be equally useful. Thanks.
JFB from Italy

How to send an analog output signal on same axis running a stepping motor umi 7764/ PCI7334

I am running a single axis stepping motor (which is working fine) but
for the application I need to be able to turn on and off a 5 volt
laser. It notes in the manual for the UMI 7764 that the the
analog output can be used as a general-purpose voltage output. I
would like to use it as such, but can't figure out what VI's actually
send messages to the board to output a 5 Volt signal.
Ideally I would use the analog output on the same axis that the
stepping motor is on, but if need be I could use one of the other axis
if this isn't possible (ie. it may not be possible to step and send
analog voltage output on same axis at same time). I have been
looking at the configuring DAQ and ADC stuff, but can't seem to make
sense if these actually control the analog output channel. I
think they just control the Analog input channels, but maybe I am
wrong.
Any help would be greatly appreciated
Andre

Hi,
It is possible to send analog output out of the same same DAC channel in which your stepper is connected, if you configure the stepper as open loop in MAX. I've tried it. This way you have the stepper output, analog output and encoder input acting independently. So you can use these seperately for different purposes, such as using the analog output for constant speed motors where speed or position control is not of much importance, encoder for positioning some other axes and stepper output for stepper control. With good programming skills, the NI motion controllers can thus be used for the most complex configurations. Great work NI !!! Nothing is impossible.
Regards,
Giridhar Rajan
Automation Engineer, Design
Cruiser Controls
Mumbai, India

Simultaneous analog output

I am using PCI-6052 with (LabVIEW) .Where two analog outputs are available ,DAC0 and DAC1.I want to simultanouly output the different waveforms on each Channel at the same time.Time is important.
I tried it with two DAQ assistance vi's setting each channel on each vi ,but at time randomly one vi's gives output not both at the same time.
Thanks
Haider

Hello Haider,
It sounds like you are trying to get started with NI-DAQmx and want to
output separate signals on the two analog output lines. The
restriction of the hardware is that all of the analog input or output
channels must be contained with in the same DAQmx Task. There are
a couple ways to do this.
If you want to stick with the DAQ Assistant, I searched our KnowledgeBases and found the following example program which does analog output for two channels using the DAQ Assistant.
If you would like to drill down a little farther and use the lower
level DAQmx VI's, I would recommend looking at one of the shipping
examples, the format for multiple channels is Devx/AOy:z where x is the
device number, y is the starting AO channel, and z is the final AO
channel.
Also, another good reference, especially if you are going to use the lower level VI's is the Learn 10 Functions in NI-DAQmx and Solve 80% of Data Acquisition Applications Tutorial. Hopefully,
that'll get you going with your program. Let us know if you have
any other questions with either the online example or one of the
shipping examples.
Regards,
Micaela N
National Instruments

Using analog outputs in labview with

I have recently started using the USB personal measurement device PMD1208-LS from measurement computing with labview. I am having problems with using the analog outputs in labview i keep getting error message 41 "This function can not be used with this board" The outputs are working fine when tested with the supplied software but not when using the Aout vi in labview. has anybody else had problems with this and know how to resolve them? I have the analog inputs all working fine in labview.
Thanks

I have used the PMD12208FS and I used this vi to use the analog outputs for it. I obtained it from Measurment Computing ftp site. The data value is in mV. Hope this helps.
Attachments:
PMD1208FS_AOut_lv61.vi ‏17 KB

How can i deliver a single pulse of varying amplitude using Analog output and USB-6251?

I am trying to generate an analog output for the following waveform:
Pulse width: 300 usec, Frequency 40 Hz, Amplitude is following a sine wave with a 2 second period.
My approach is: Use an async timer with 1/[40 Hz] sec interval. I set the DAQ output rate at 1 MHz and the approach has been to generate and write 300 samples of the amplitude I need to send out, then wait for the next async interval callback , update amplitude etc etc. The assumption is that once the 300 samples are written and the task started , a 300 usec pulse would be sent out , task then stopped and then the analog output would be set to 0 waiting for he next pulse. The reality is that I get a stream of pulses of 300 usec which last the whole timer interval.
So , trying to establish whether what I am trying to do is feasible without actually sending a large array to the USB-6251 which would write zeros for the period after 300 usec.
Here is my timercallback code for review:
    switch (event)
        case EVENT_TIMER_TICK:
            DAQmxErrChk(DAQmxStopTask(TaskAnalog));
Determine Voltage value algorithm here
           //Generate Waveform and start Task
           //Prepare AO arr
           for (k=0;k<300;k++)
               AOArr[k] = 0;
               if (k<G_PulseWidth)
               AOArr[k] = VOLTAGE_OUTPUT;
           if (AOArr!=NULL)
               DAQmxErrChk(DAQmxWriteAnalogF64 (TaskAnalog, (int32) 300 , 0, DAQmx_Val_WaitInfinitely, DAQmx_Val_GroupByChannel , AOArr, &sampsPerChanWritten, NULL));
            DAQmxErrChk(DAQmxStartTask(TaskAnalog));
           break;
Thanks

I did resovle the issue I encountered. It was due to bad configuration of the Task.
My initial configuration was:
DAQmxErrChk(DAQmxCfgSampClkTiming(TaskAnalog, "",1.0E+06, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps , 300 * 1.0E+06));
which should be:
DAQmxErrChk(DAQmxCfgSampClkTiming(TaskAnalog, "",1.0E+06, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps , 300));
THis did it. works very well.
THanks

Multi channel analog output

I'm trying to make analog output pulses of microsecond order
via 3 output channels.
I try Daqmx write for that goal..and I can make single channel
pulse with pulse vi in Signal processing category
But ,I have difficulty in make pulses for more than
two channels.
When I try , Labview always make error(that I can't understand)
or do not make signal at all.
I also tried to make analog output for DC ,and it works.
I don't know,however, how I can modify this for pulses.
I will link screen captures of my labview program.
http://www.mylv.net/include/file_download.asp?file=/qna/data/PULSE.JPG&size=80854
http://www.mylv.net/include/file_download.asp?file=/qna/data/MLTI(0).JPG&size=63567

ok i made you a small application in LV 8.2
it might not work at first try, so you will have to play around and modify as needed.
you have an array that define the pulse width and relative phase for every channel (every line of the array defines a channel, in order). it is then transformed into a 2D data array, and sent to buffer.
this approach will work as long as there is a proportional relation between the rate of output and the width of pulses, to avoid underbuffer problems.
ifyou have to update lots of channels lots of times, then you might want to cycle your writing trough the buffer.
dont forget to write in the "physical adresses" control the ful list of channels used.
Message Edited by Gabi1 on 11-29-2007 01:19 PM
... And here's where I keep assorted lengths of wires...
Attachments:
multichannel pulses.vi ‏35 KB
multichannel pulses.png ‏14 KB

Data Rescue II AND Disksaver for failing hard drive?

I need some guidance on rescuing data from an internal hard drive that Disk Utility could not fix. (The drive is making an odd noise, and apparently has a mechanical problem.)
Data Rescue II appears to successfully cloned my iMac's drive, while Carbon Copy Cloner and SuperDuper froze when I attempted to use them on it.
I just finished my cloning of the problem drive with Data Rescue II last night, and I'm debating my next step. I bought Diskwarrior as well, but haven't opened the box yet.
Should I now use Diskwarrior to build a new directory for the clone, or is that new directory generated by the Data Rescue cloning? Also, can you boot from the clone created by Data Rescue II?
I'm thinking of having a replacement drive installed in my iMac, then cloning back to it from the clone I made last night, if it's healthy. Any thoughts?

Gary,
Always interested in drive failures (and trying to avoid 'em!)
Saw a link on StorageReview to a study done by Google:
Predicting hard drive failures
Its a study by some Google employees on the failure rates of disk drives deployed within their infrastructure.
Failure Trends In A Large Disk Drive Population
Examining the population of hard drives under deployment within Google
* In general, there are around four ways a HDD will fail. Firmware zone corruption, electronic failure, mechanical failure, and logical corruption. Unfortunately, S.M.A.R.T only handles a subset of the "mechanical failure" category (mainly media failure and thermal failure), and does not protect against single instance/incident catastrophic mechanical errors (head crash, spindle/servo motor failure, stick-shun).
* I was surprised about the lack of correlation found between elevated temperature and expected drive reliability. The graph only went up to 50 C, though, and I would expect a much stronger correlation once the temperature reached beyond typical max temp specs.
* I give props to the google crew for their SMART correlation analysis. I would have loved to see a quick postmortem on all of the failed drives to determine cause, and a breakdown into the top four categories.
* Side note, logical corruption may lead to data loss, but it does not necessarily mean that the HDD has failed.
Findings:
* After a first scan error, drives are 39x more likely to fail within 60 days.
First errors in reallocations, offline reallocations, and prob ational counts are also strongly correlated to higher failure probabilities.
* A large fraction of our failed drives have shown NO SMART error signals watsoever.
* There was a lack of a consistent pattern of higher failure rates for higher temperature drives for for those drives at higher utilization levels.
* Some of the charts point to drive failure early on, a "survival of the fittest" perhaps.
http://labs.google.com/papers/disk_failures.pdf
SMART is not that reliable at predicting, of course if it shows a problem, it is just that much worse. I try to torture and kill a drive right off the bad, if it survives the first week of abuse, it is probably going to survive anyway. But being paranoid, never leave data to chance, assume that it will some day fail or at least need to be reformatted or retired.
Mac Pro 2GHz 4GB 10K Raptor 23" Cinema Mac OS X (10.4.8) WD RE RAID DW 4.0 APC RS1500 Vista

Using DAQ generate a 38kHz on an analog output on and off for ms using labVIEW

I wish to generate a 38kHz pulse on an analog output of a mydaq to drive a infrared led. The 38kHz signal is not continuous but is on for 1ms and off for 1ms.

Hi pat,
you generate a waveform using 38kHz as sample rate and a rectangular shape of 1ms HIGH level and 1ms LOW level. Using some simple math you will notice you need 38 samples at 38Khz to output a value for 1ms…
Then you just output that waveform on a AO channel.
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome

Loop in combination with Analog output

Hi
I have modified the script thats translate a value in to a static analog output voltage. The value comes from another online running application. The analog output value must remain static until a new value arise. I'm using VB6 and DAQmx 8.5 on a XP computer. The DA converter is NI USB-6211. I have tried to play around with the Start/Stop and clear commands but my script still makes the program highly unstabile.
So am I using the commands correctly?. And have I setup the write commands correctly too. Can anyone allso explain how to use the command Doevent correctly
Dim taskHandle As Long
    Dim clockEdge As Long
    Dim sampsPerCycle As Double
    Dim desiredSampleClockRate As Double
    Dim resultingFrequency As Double
    Dim amplitude As Double
    Dim numSampsPerChannel As Long
    Dim numChannels As Long
    Dim errorCode As Long
    Dim errorString As String
    Dim sampsPerChanWritten As Long
    Dim XICVolt As Double
' Create the DAQmx task.
    Call DAQmxCreateTask("", taskHandle)
    ' Add an analog output channel to the task and check to see whether there is only ONE task.
    Call DAQmxCreateAOVoltageChan(taskHandle, "Dev2/ao0", "aoChannel", "-10", "10", DAQmx_Val_VoltageUnits2_Volts, "")
    Call DAQmxGetTaskNumChans(taskHandle, numChannels)
    If numChannels > 1 Then
        errorCode = -1
        errorString = "Please specify only one channel."
        Err.Raise errorCode, , errorString
    End If
Data_is_recorded:
    If Actualcycles = expectedcycles Then
    GoTo end_script
    Else
    If Actualcycles > lastcycles Then
    DoEvents
     Call DataPoint.GetDataPoint(thenumberOfDataPoint, theXvalue, theYvalue)
        XICVolt = (theYvalue / 10000000#)
    ' Write to the desired channel(s).
    Call DAQmxWriteAnalogF64(taskHandle, 1, True, 10#, _
        DAQmx_Val_GroupByScanNumber, XICVolt, sampsPerChanWritten, ByVal 0&
    Else
     lastcycles = theWF.GetActualNumberOfCycles(sampleIndex, 0)
     End If
    GoTo Data_is_recorded
end_script:
End If
call DAQmx.stopTask(Taskhandle)
call DAQmx.clearTask(taskhandle)
Best regards
Peter

David Weber wrote:
thanks lot for all the great feedback. That's really helpful. I think I'll go for the NO_MERGE hint. A first test with this looks good.Keep in mind, only undocumented hint MATERIALIZE along with subquery factoring clause WITH (for which this hint was created) will work in real queries:
SQL> select my_id as id
2       , my_id as same_id
3 from (select /*+ NO_MERGE */ xxx_test_pkg.get_id(1) as my_id from dual),emp where rownum < 6;
        ID    SAME_ID
        20         20
        21         21
        21         21
        21         21
        21         21
SQL> select my_id as id
2       , my_id as same_id
3 from (select xxx_test_pkg.get_id(1) as my_id from dual where rownum=1),emp where rownum < 6;
        ID    SAME_ID
        22         22
        23         23
        23         23
        23         23
        23         23
SQL> select my_id as id
2       , my_id as same_id
3 from (select /*+ MATERIALIZE */ xxx_test_pkg.get_id(1) as my_id from dual),emp where rownum < 6;
        ID    SAME_ID
        24         25
        26         27
        28         29
        30         31
        32         33
SQL> with t as (select /*+ MATERIALIZE */ xxx_test_pkg.get_id(1) as my_id from dual)
2 select my_id as id
3       , my_id as same_id
4 from t,emp where rownum < 6;
        ID    SAME_ID
        34         34
        34         34
        34         34
        34         34
        34         34
SQL> SY.

PCI Card for Analog output in the range of 10mv

dear ni,
                I want to know about the PCI card that can be generate analog output in the range of maximum 10mv. i am going to use for caliberation of loadcell, strain gauges devices.
could you tell me on which PCI card will support this type of application.
Regards,
Balaji DP

Try: http://www.ni.com/dataacquisition/
These have analog output voltages < 10V:   http://sine.ni.com/nifn/cds/view/main/p/sn/n12:7604,n3:7853/lang/en/nid/1036/ap/daq
You need something with a high bit count to get good resolution at 10 mV, such as the PCI-6010 which has a 16 bit D/A.
Here are the minimum voltage specs for the 6010:
Minimum Voltage Range
-0.2..0.2 V
      Range Accuracy
283 µV
      Range Sensitivity
6.4 µV
Message Edited by vt92 on 11-18-2009 07:56 AM
"There is a God shaped vacuum in the heart of every man which cannot be filled by any created thing, but only by God, the Creator, made known through Jesus." - Blaise Pascal

Optical/Analog Splitter for Dual Audio Output

Does anyone know if the mini-TOSlink combo jack can simultaneously output both digital and analog signals? If so, has anyone seen a splitter that would let you take advantage of this? I need both output formats to feed into my multi-zone stereo receiver.

I am currently trying to find a solution to what is I think the same problem (receiver only routes analog signals to the additional zones). I haven't been able to find such a cable and have considered these to connect to my multi-zone receiver:
1) I have an old sound usb soundblaster extigy. I have used it in the past as a cheap d/a convertor of sorts as it has both digital input and outputs and works without being hooked up to a computer. If I feed it the airtunes digital signal it outputs simultaneously optical and analog to the receiver. The problem is that the soundblaster does add processing to the signal (volume control and mixing of its other inputs) so although it does sound clean, it almost defeats the purpose of the digital connection. This adds another unit and may not be ideal for you as you would have to buy such a card. Separate D/A convertors would also work but would add even more cost
2) I have considered taking my airtunes apart and tapping into the audio output and adding a second analog output. My warranty is already up but I am afraid the case of the airtunes cannot be opened without it breaking. This option does not fix the same audio distribution problem when I hook up my laptop.
I thought the integrated digital outputs on my macs and airtunes were ingenious till I ran into this problem with my new receiver. Too bad the receiver doesn't have a couple more D/As to route digital signals. With the number in there already for 7.1 channel audio I feel this shouldn't be a problem at least when listening to stereo digital signals.
Sorry for the long post, I will keep looking for a better solution, please post if you do as well!

Is inactive analog output will be at high impedance or cut off state?

Hey
I'm using the NI 6229 analog outputs.
I would like to know if there is a tri-state or high impedance state for those analog output when it is not in use?
Solved!
Go to Solution.

Hello amco,
From the description of your project, I'm envisioning two probes attached to different points along a single trace on a PCB.
It is certainly not recommended to have two analog output lines attached to the same channel. As you have experienced, the behavior is unpredictable. In a worst-case-scenario, one could potentially damage the AO line that is not actively driving the channel.
So we do need to find a configuration that makes the unusued AO channel electrically separated from the channel-under-test. One option would be to introduce an electromechanical switch. This will add some complexity to your setup and your code, but it will permit you to send the signal from AO-0, disconnect AO-0, connect AO-1 and send a signal from AO-1 — all in a very short amount of time.
Best regards
Matthew H.
Applications Engineer
National Instruments

How to combine the analog input and analog output vi's

Hi !
I have a perfectly running triggered analog input acquisition vi. I have a seperate vi for analog output that's running perfectly too. Can someone tell me how to combine these two operations so that I could get a vi that does simulataneous AI and AO without missing triggers. I have tried all the different kinds of configurations suggested by NI support but nothing seems to work. Can someone help ?
thanks,
Shiva
Attachments:
dac_good.vi ‏77 KB
adc_good_fw.vi ‏124 KB

Shiva;
I'm attaching a good Application Notes that shows how to synchronize multiple DAQ tasks, in Labview.
Hope this helps.
Filipe
Attachments:
Advanced_Sync_Techniques_for_DAQ.zip ‏166 KB

Combine Analog outputs for higher current drive

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