Analog output is inactive will be high impedance or cutting State?

Similar Questions

• How to make accurate measurements at high impedance using NI USB DAQ 6343 in Labview

  Hello.  I use a DAQ 6343 for measurement of analog voltage on a signal of high impedance.  I am aware that low impedance is recommended, but it is what is on my Board.  I tried to measure several times to an A/D channel only, increasing the number of samples, sample rate reduction, and I find significant variations in all of the measures.

  I wonder what is the best way to stabilize the A/D before taking a step on the way to analog input?

  Thanks in advance for your help.

  Jodi

  Hi jschwatz100,

  Here is a good link on ghost image, which talks about solutions for playback of a signal from a high impedance source:

  http://digital.NI.com/public.nsf/allkb/73CB0FB296814E2286256FFD00028DDF?OpenDocument

  I would recommend a circuit follower of simple tension of construction as a buffer between your signal source and data acquisition. Here is a Wikipedia article about it:

  http://en.Wikipedia.org/wiki/Buffer_amplifier

  I also recommend to maintain a ratio of 10:1 for your sample rate: Buffer Size(N Samples in Continuous Mode) and lowering/raising them both the same way.

  DylanC

• read the output of a path of analog output current voltage

  In DAQmx if you are unsure of the status of a digital output port, you can take a reading on this subject.  When I try this on an analog output, I get an error.  Is it possible to query the status of the output of an analog output?  I realize that I could follow the State with a variable, but a direct reading would be really handy.

  Hello, GIS.

  There is no way to read the output in the AO modules without wiring physically the signal to a module to HAVE.  You are able to use a variable to read the current value of the output, as you mentioned earlier.

  Channels AO multifunction boards, however, can be read through tasks of entry by rounting in-house channel to read ao vs aoground.

  Lisa

• USB-6501 Z (high impedance)

  I am using the IDW library to create a master by using the USB-6501. My problem is that the DAQmx write gives an error when it tries to use the 'Z' setting for high impedance. Are there workarounds for this?

  6501 does not support high impedance state... inexpensive compared to high-performance and you have a low cost DIO.

  Might be able to set the output to an entry, but there is still the internal pullup with that you will fight.

• Analog OUTPUT material

  Hello

  My question is about the analog output (0 - 10V) of the myDAQ unit.

  On the card, you can read:

  "Overdrive Protection +-16 V forever."

  Lets imagine the worst case: 0 V output DQA, but outside a battery or anything else is connected with 15 V to the analog output.

  Fact an "unlimited" current in data acquisition or protection 'Overdrive' works here and the material is safe to destroy?

  The background: I want to OD are protected from transient voltages and toilet on a simple zener diodes clip or a tvs diode...

  Thank you all, Markus

  Markus,

  To use a zener diode as protection, you must also have an impedance of current limiting in series with the source against which you are protecting.  The manual for the device of maDAQ indicates that the lines of the AO are pushed by OPA1642 op amps.  TI the MSDS for this unit shows the current limiting internal ~ 36 my short circuit with Earth and a thermal shutdown circuit that tries to protect against the terms of overpwer.

  However, under your 15 V battery, 11 V zener and 0 V programmed DAQ exit, the situation may be different.  The current from the battery through the zener will be limited by the impedance of cables or any type of resistance on the line.  This has no direct effect on the myDAQ device, but it will probably destroy the zener unless resistance limits the current to a lower maximum current nominal zener.  As long as the voltage at the output of the myDAQ is lower than the internal supply voltage (+/-15 V), on the OPA1642 current limitation should apply.  With 11V applied to the output and the value set to zero the device would probably be to try to sink the maximum current for-15 V power supply.  Which translates to a dissipation of power of more than 900 mW, which exceeds the rated capacity of the op amp. Themal protection should, in principle, reduce the current to a level that does not exceed the thermal limit under development.

  This test can be a costly process. The unit may be destroyed.  Given that the maximum current specified for an analog output channel is 2 my and the maximum voltage is 10 V, I would consider a series resistance of perhaps 1000 ohms and clamping schottky diodes at the + 15 V and - 15 V power supply.  This will limit the current to 10-20 my in all conditions you have mentioned and would also provide protection to the case where the battery is connected the myDAQ device is turned off. He alsoe does not care about the polarity of the external source.  It will drop the output voltage according to the load impedance.  If this should be used in a student lab, the calcualtion of this decline is something they should be doing anyway, and would be a small price to pay for protection.

  Lynn

• How of current analog output more than 2mA

  Hi, I have designed a simple PID loop to control the input of a device voltage. My camera has an Ohm resistance. I found that being controlled input voltage may not exceed 0.6V, then I realized that the maximum output current is my 6211 NI DAQ 2mA. But I really need more 2mA (Max is 10mA). I tried to use a voltage follower because it has high impedance imput and low output impedance, but it does not work. Could someone tell me a method to solve the problem?

  Thank you.

  CJL

  

  100nF caps | with 10µF,.

  R optional...

  What OP do you currently use?

  Without this connection GND current can flow so you will stick to 0.6V as without a driver.

• Analog outputs with different time scales

  I use products AO of a card PCI-6731 for an application scan head and I have some difficulties to achieve peak performance, that I need. I am contolling the map with nidaqmx drivers in c ++

  Basically, an output controls scanning in the direction Y (which is a line of scanning and is very fast) and the other in the X (increment once per scan line, so much slower). The complication is that both exits start at an external trigger, because positioning is synchronized to a separate data acquisition card.

  Now, what I do is:

  -write the scanline for 0 output waveform

  -set output 1 to a given position

  -say next Trigger output card

  -hangs at the end and stop tasks

  What I really want to do, it is just tell him to start with on each external trigger output waveform of scanline 0 and output 1 increment to the next position. So I could do a complete 2D scanner with a minimum of control software.

  Any ideas on how I could best achieve this? My understanding of the nidaqmx drivers I don't see an elegant way to do it.

  I could potentially do some operations on the done callback, although it makes me a little nervous because the control PC running windows, it is not a real-time operating system.

  Hmm I do not know exactly but there are a couple of things (it is close)...

  The output frequency of meter in your example 5 MHz (20 MHz, 2 high ticks, weak 2 ticks), which is faster than holders 6731 for a sample clock.  I thought that this would have given a material error... are you looking for errors once the task runs (for example using DAQmxIsTaskDone)?.  There is a DAQmxCreateCOPulseChanFreq if you want to set the clock frequency directly (it will use the appropriate default internal time base).

  The task of counter generates 1000 pulses per trigger, is what determines the number of samples generated by the trigger (I assume that you want it to be 1024 aka "numSamples").

  The analog output task must either use:

  (1) calendar continuous if the output will repeat indefinitely as several triggers are acquired.

  (2) finishes pitch (N * numSamples) samples where N is the number of lines that you want to exit and numSamples is the number of samples per line.  In this case, the task will end once the lines were triggered.

  Best regards

• Strange analog output of USB-6211

  I just got USB-6211 to replace USB-6001 to set the clock to external sampling on analog output for LED lighting control. The part of external clock example works fine, but the analog output voltage is strange. To do self-monitoring, I connected control pin LED to AO0 & AI0 of surveillance in the NI MAX test panel and LED control on the ground at AO - GND & GND HAVE since I have both USB-6001 and USB-6211, I conducted tests on two of them with the same setting of wire. When I generate sine wave - 5V to 5V to AO0 (from NI MAX test panel), USB-6001 can monitor the same signal AI0, but watch USB-6211 - 3, 4V to 3.4V voltage truncated. I did the test separately (wiring one device at a time), so there is no interference between the two devices. USB-6211 past self-calibration and self-monitoring. Also, I did reset devices. I don't know why they would behave differently with the same configuration, and I hope that someone could help with this question. Thank you.

  Hi skuo1008,

  The USB-6001 can support + / 5 output current my from terminals to analog output, while the USB-6211 box can provide only +/-2 my current output.  It is likely that the load impedance is too low, causing the 6211 to hit its current compliance and thus cut the tension.  If you try to exchange your load with a resistance of at least 5 v/.002A = 2500 Ohms, you should be able to see the full +/-5V sine wave.  I suspect that your DUT has a words 3.4V/.002A = 1700 Ohms impedance.  You could use a device with higher output current or use a more current source buffer circuit.  If you do not need a bipolar output, you might also consider using digital lines to control the LEDs.

  Kind regards

• Decent analog output of my Qosmio F20-154

  I use my Qosmio as a Microsoft Media Center with my TV connected via VGA output. It gives me a pretty good image.

  However, my TV does not support most of the modes of zoom for VGA; or it does for DVI or HDMI.

  So I tried the image output via S-Video - which produces a shitty and unacceptable photo.

  Unfortunately, Qosmio has no TV output, so I can't try it.

  So, does anyone know of a piece of hardware that can be used to make the Qosmio to produce a decent analog output, such as TV-Out (antenna) or Composite?

  Thanks in advance,
  Brian

  As far as I know you have only two options to send the video signal.

  Qosmio F20 supports viga video and s-video ports.
  So either you will use the video VGA (15-pin) port or output video super TV (S-Video) 4pol mini to connect the TV to the laptop...

  I have connected my laptop to the TV also using the s-video port and the photo quality is OK.

  Please check you s-video cable and if possible test another in addition, I would recommend check some settings on the TV and s-video option

• To input analog shutdown when the analog output is completed and synchronization

  Hello

  I'm trying to get my LabVIEW program to send analog output to a computer and read acceleration using the cDAQ-9184. Chassis output that I use is the NI 9263 and the chassis of entry is the NI 9234. I generate a signal of white noise using LabVIEW Express signal generator.

  The first problem I have is the synchronization. I had an old VI that has begun to measure the acceleration just about a second after the entry has been given to the machine. I used the LabVIEW tutorial on how to sync the analog input and output, only to discover that it does not work with two different hunts. Then I found another tutorial that shows how to synchronize different frames between them.

  The second problem is the cessation of the LabVIEW program. What I want to do is to generate the signal and then simultaneously send and read the input and output analog, respectively. It is because I don't want a phase difference or any shorter signal for a direct comparison. But as soon as the signal is sent to the machine, I want the entry to stop analog playback and then then the LabVIEW program must stop. I want to be able to choose any length of signal to be generated and stop as soon as the entire duration of the signal has been sent to the machine.

  I tried 'DAQmx stop', "DAQmx Timer" and 'DAQmx's task made?' and none of them have worked for me. It is also my first time on a forum posting, so I hope I gave enough information. I enclose my VI as well. The VI shows I read an entry for the analog input voltage, but I am only using this to try to get to the work programme.

  I'd appreciate any help I could get.

  Thanks in advance

  Peter

  Hi Peter,.

  I have some recommendations for you that I think you will get closer to your solution. First of all, I assumed you meant that you had 1 chassis (cDAQ-9184) who had two modules in it (NOR-9263 and NOR-9234). My next steps are based on this assumption, so if it's wrong, please let me know.

  For your first question about the synchronization, the code you provided is very close to what you need. You need to do, however, implement architecture master/slave for startup tasks DAQmx functions. To do this, you can add another frame to the flat sequence structure and put the master start task (input voltage) after the start slave (output voltage) task.

  To manage your second question and that the program ends at the point where you, the first step is to get rid of all the logic that you use with the local variable of length of time. Rather than use this logic, just wire the node "task performed?" of "is task performed?" operate to stop the loop. This will cause your loop to stop as soon as the signal is sent to the machine.

  I have some other recommendations for you that will increase the performance of your program:

  (1) rather than writing on file inside the last loop, you can use the DAQmx Configure Logging (PDM) .vi. You will place this VI between DAQmx Timing.vi and DAQmx Start Task.vi to the task of the analog input voltage.

  (2) after the last while loop, you want to stop the task and analog outputs as well with another DAQmx stop Task.vi.

  (3) rather than using a local variable for the entrance of displacement and wiring it in the DAQmx Write.vi, you can wire directly from the output waveform of the wave to build function node.

  That should help you get started in the synchronization of these tasks.

  -Alex C.

  Technical sales engineer

  National Instruments

• How can I check if the counter entry is synchronized with the analog output?

  Hello

  I'm working on an application for counting photons.  I use two channels of analog output on a PCI-6713 card to send a frame model to a set of XY scan mirrors.  I then a photon count unit that emits a TTL signal when the photons are detected as a result of this raster analysis.  I then use a surfboard USB-6211 to count the edges on this TTL signal.

  I have problems that seem due to synchronization problems.  I use the sample AO on the PCI-6713 card clock like the door of my meter on the map USB-6211.  I use a trigger to start digital to analog output and a trigger of arms for the entrance to counter early. Is there a way to check that the analog output and counter entry of start of operations at the same time and are are synchronized?  I basically want to monitor and compare the ao real sample of the PCI-6713 card clock door signal used by the jury of the USB-6211.  I was able to export the sample AO clock and watch it on my oscilloscope, but not the signal from the door of the USB-6211.

  Thanks for your help,

  Brian

  Update... It turns out that there is no problem of synchronization between my meter input and the analogue output.  There was a difference of impedance when I connected my unit of counting photons to my USB-6211.  This caused an error variable count rate.  After accouting for this shift, the problem disappeared.

• How to control the two analog outputs at a time

  I'm new to LabVIEW and have some problems in DAQmx with control outputs analog multiple.

  I want to set up a platform using BNC-2110 and PCIe6363 to control two rotating mirrors. The problem that I can only give an output (AO0 or AO1) at a time and I really have no idea how revise my LabVIEW diagram to control two outputs at the same time I met. I tried to change the outputs and it keeps a mirror turning instead of the old. Could someone help me with my problem and I would really appreciate. This is my blocked diagram and front.

  

  

  Hi zrmaker,

  As mentioned by RavensFan, you should not create 2 analog outputs different tasks if you use AO0 AO1. To your façade > physical control or the channels > select the drop-down list of the control channel physical (s) > Browse > hold down the CTRL + select the AO0 and AO1 > Select OK. Once this is done, you will see that your control or the physical channels has the following input values: "Dev1 / ao0:1" which means that you will access to AO0 AO1.

  In regards to writing DAQmx, simply select Analog > multiple channels > samples multiple > 1 waveform (you should get the following: 1 d Analog Waveform NChan NSamp). Once done, you can just use table build to combine 2 different waveforms and plug in this table to DAQmx writing output. The first index will be the output for AO0 value and the other will be for AO1.

  You can check this link on how to read or write from several channels: http://digital.ni.com/public.nsf/allkb/0C1ADEF06A54AB2D862575040066FD51

  Additional reference:
  http://www.NI.com/white-paper/2835/en/

  Hope that helps.

  Warm greetings,

  Lennard.C

• How can I pause and resume the analog output using DAQmx?

  I use a DAQ hardware to produce an analog waveform.  I would like simply to break the output of the wave and then resume where it left off.  I use DAQmx and LabVIEW 2011.

  I've seen examples that use a digital or analog break trigger, but I would take a break in the software only.  How can I do this?

  -Joe

  Hi Joe!

  I spent some time thinking about it and I realized that you can technically use a fundamental mission of the analog output, as you previously wrote that runs continuously. However, the generated output samples are controlled by the sample clock pulses, and can be manipulated to fit our needs "suspension."

  To do this, we will need another counter task that generates a pulse train (see our examples of shipping under material input and output > DAQmx > generating digital pulses > generate dig Pulse Train - Continuous.vi) that stops and starts the user to choose. This can be in another quite VI or controlled by software. We will use this as the task of our output sample clock.

  Then, the task of the AO, wire a constant to the sample clock source and select ' DevX/CtrXInternalOutput"based on the counter that you specified in the task of counter. You will need to choose "I/o name of filtration" and check the box that says "include advanced terminals' and right-click of the constant. See picture attached as a reference. In this way, the task of the AO is constantly running, but it generates only actually all data when the meter running task.

  

  Let me know if you have any questions!

  Have a great day!

• Generating analog output signals 4 with different frequencies

  Hi all

  I was trying to say to generate 4 different signals at different frequencies

  1. first waveform is a sine wave with 5000 Hz,

  2. other with 8000Hz,

  3. third, one is a square with 25 Hz waveform and

  4. fourth one with triangular waveform 50 Hz

  all waveforms must be generated simultanoeusly.

  I tried to generate with the task unique analog output and sample clock (clock rate is 100000). Cross in scope that I see only 5000 and 8000 Hz we generated correctly and the rest two waveforms show the incorrect frequency.

  I guess that's due to the frequency of high clock to sample for more low frequencies for ex 25 Hz and 50 Hz. If I reduce the clock rate to get the lower frequencies properly so I can't generate frequencies higher correctly. (there's a clsh between frequencies and the clock frequency)

  Is it possible to use DAQ board master sample clock and its magnitude downward revision (everywhere where it is necessary for each waveform separately) to generate all the signals at different frequencies at the same time in a single task?

  
  

• Redeclenchables/continuous to a custom waveform analog output?

  Hello

  I try regular output an analog signal using the box USB-6211 and Labview2009. I looked at various examples of waveform, including the retriggerableAO.vi example, but I can't seem to understand how to send a 'waveform' custom stamp (terminology is perhaps the question). In all the examples (including waveformbuffer), I ran across the single waveform, the options are sine, square, etc.  Previously, I posted on this forum looking for hardware suggestions (link here) and explained what I try to do and got the big help. To sum up, I would like to read a 'waveform' from a text file, send it to the usb-6211 buffer and then continue to an analog channel. At the same time, I'll use the beginning of the analog task to trigger a digital signal once per cycle as well.

  I got in what concerns the establishment of the waveform, but am stuck to figure out how to get into the buffer and setting the frequency, etc.

  Thank you

  Gabe

  Hi Gabe,

  Dennis is correct that it will take some room to modify the existing screws to fit your need.  As he says, the Con Gen tension Wfm - Int Regeneration.vi Clk - no example provided with LabVIEW.  In the example, it can be shown that there is a custom VI used to explain the problems that arise when a waveform of a given frequency to a frequency of sampling and outputs analog specified.

  With all that said, it seems you want to read from an existing waveform file that you created and this waveform to an AO output channel.  There are a few things that will be needed to know before proceeding:

  -What is the waveform as you try to output (5000 samples, 10 k, 100 k, etc.)?

  -What pieces of the size of the wave you want output (100 samples at a time, etc.)?

  -you want to again and again, or simply run through once the waveform looping?

  Assuming that you already have the waveform and will only step by step, here's what I would like:

  -break the large waveform into smaller pieces of waveform of standard size

  -import the waveforms in LabVIEW and create an array of waveforms

  -bring the waveform in the example Dennis mentioned previously with automatic indexing enabled on the tunnel

  -Remove the generator of wave functions existing the while loop

  -wire your indexed table of waveform for the data of the VI DAQmx of analog output terminal

  It is possible that you will have to play with the settings of your waveform and timing of your VI, but this should be a good starting point.  Please let me know if something is not clear or if I have misunderstood your original message.  Have a beautiful reast of the day.

  Best,