Size of the analog input signal
Hi,
very simple q how to protect my DAQ card from overvoltage. i mean, i produce some signal in my vi and i want to reduce it to max. say it 30V. how can i do this?
thanx in advance
vedran
Hi vedran,
I didn´t understand your question. Do you want to measure voltage and protect your card against the overvoltage or do you produce a signal with your DAQ card? Please tell me exactly what you want to do.
PatrickB
National Instruments Germany
Similar Messages
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Can the analog inputs be daisy chained to measure higher voltages?
Can the analog inputs of a PXI-6289 be connected in series to measure higher voltages than normally allowed at the analog inputs of the PXI-6289 (i.e. 10 VDC)? For example, let's say I wanted to measure 18 VDC using an analog input channel of the PXI-6289. I would then pick two AI channels and connect the positive of one to the negative of the other and then the two remaining leads would be placed across the 18 VDC. Resistors could also be placed across the 18 VDC to form a votage divide. One AI would measure the voltage across one resistor and the other AI would measure the voltage across the remaining resistor. I have tried this and the voltage measurements appear to loose accuracy. Thank you for your help.
Hello Rafi,
You may want to invest in a high voltage attenuator for signal conditioning prior to reading the signal. The documents below may also be helpful:
High Voltage and Isolated Measurements
http://zone.ni.com/devzone/cda/tut/p/id/10693
High-Voltage Measurements and Isolation
http://zone.ni.com/devzone/cda/tut/p/id/3410
Regards,
Roman Sandoval | National Instruments | RF Systems Engineer -
How can I syncronize the analog input?
The signal coming from the microphone input of the DSP module, displayed on Waveform Graph, is "slipping".
How can I syncronize the analog input?
Thank you!Ahh! You are doing this on the DSP itself. That would explain the Express VI problem, since you probably do not have floating point available. A simple level trigger is not hard to code using integer math. You can use the VIs I mentioned above as a guide (the algorithms should work well with integers as well as floating point) or just do it yourself. A possible algorithm for a positive going edge trigger is the following:
Search array until first point is less than level and second is greater than or equal to level (use In Range and Coerce to search).
Extract array subset from your data starting at the point you just found.
If you need a particular length of data and are continously acquiring, append data from the next scan onto your data until required length is met.
If you run into issues, let us know. Remember that shift registers are your friend.
This account is no longer active. Contact ShadesOfGray for current posts and information. -
Can we acquire the Analog input and Digital Input at
Can we acquire the Analog input and Digital Input at
the same time? My sensor data include Analog and
digital signals.Hi Chenchen,
It usually simplifies things greatly if you use analog inputs to monitor both the analog signals AND the digital signals.
If you abosulutely HAVE to use digital lines, then the answer is, DEPENDS....
With the correct hardware and depending on how fast you want to collect data and how closely the measurements have to be syncronized in time, it can be done.
But first, concider using analog inputs to monitor all signals.
If you need to move forward with both analog and digital acquisitions, then post a new quesion and give us details on the hardware you are using and the other details we will need to advise you.
Trying to help,
Ben
Ben Rayner
Certified LabVIEW Developer
www.DSAutomation.com
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction -
I am using the PCI-7344 to control my system. The analog inputs are connected to the output of my system while the analog outputs serve as feedback to the system. The system is a servo. I want to know what is the conversion between the voltage read at the input, to card counts, and finally to the voltage output to the system.
Carole,
If you are trying to do analog feedback with a servo motor, Chapter 14 of the manual talks about how to set up the torque feedback. Also linked below is a LabVIEW example of analog feedback.
Chapter 14
NI-Motion User Manual
Automatic Analog Feedback with FlexMotion example
A. Talley
National Instruments -
Problem with the analog input acquisition in labview fpga 8.5.1 and CRIO
Hello all,
I am using NI CRIO 9104 RT controller with 9014 FPGA chassis.I am using an Analog input module 9205.My problem is with the acquisition.I am using a
function generator which generates some sine wave of -1 to 1 ,5hz to125khz sine signal and i have connected to 9205 in rse mode.In FPGA vi i had placed the I/O node and placed an indicator(data type FXP).If i connect the i/o node to a chart or graph,i am not able to see the output.?How this problem can bbe solved
Next i had placed a FIFO in DMA transfer mode of depth 1023 which will accept the U32 datatype,so i did some manipulation as mentioned in a tutorial.
Now in RT VI i am reading the same data from the buffer in U32 and doing the reverse manipulation i am able to view the data.Now the problem is ..if i am
increasing the frequency of the input signal,the data is completly lost ?How can i overcome this problem...
thanks in advance,
srikrishna.J
Analysis Engineer,
NeurofocusDifficult to see where is the problem ....
Be sure you are doing a good RT system by grabing reference design examples
Don't forget to specify the DMA FIFO size in the RT code
Doesn't matter the size of the DMA size under the FPGA project explorer.
Upload your code, You will get answers...
Mathieu -
How do I use the analog input (ADC) to drive a motion profile in MAX
We are trying to use an anolog input signal from a DAQ card to control the motion contol axis. For now, we want the motor speed to follow a sinusoidal voltage waveform, and later on, we will be using a more complex velocity profile.
In order to accomplish this task, we have searched the user forum, and found information suggesting to operate the servo motor in 'slave' mode under the 'gearing' option. Therefore, we have set the Gear Master to 'ADC Channel-1', Mode set to 'absolute', Gear ratio 1:1, and provided the sinusoidal voltage (+/- 5V, 3 Hz) to the AIN1 connector on the MID-7654 controller. When using the 1-D Interacitve 'single axis' control panel, the motor runs at constant speed in one direction only. It does not react to the sinusoidal speed profile request as we expected.
How do we 'turn on' the 'slave' mode in MAX? Please talk us through the necessary steps and settings? Thanks.
StaffanStaffan,
you can configure and enablethe Gearing mode in MAX and it should be activated after saving the settings and initializing the board. In 1D-Interactive you can't use Gearing. For better flexibility I recommend not using MAX for configuring and enbling Gearing. You better should do this in your application.
In fact there is a perfect LabVIEW-example that ships with the NI-Motion driver (Master Analog Input - Slave Axis Gearing.vi)
I hope this helps,
Jochen Klier
National Instruments
Message Edited by Jochen on 10-02-2007 08:37 AM
Attachments:
gearing.jpg 162 KB -
How to making smooth the analog input.
I am trying to get an analog input from a device (torque meter). sending trough compactRIO and using NI 9025 analog module.
can get the signal, but too noisy. so how to make it smooth.
any suggestion what to use and what to do. pleaseactually I am trying to get analog input from a torque meter, the input is voltage,
and I am used the NI 9073 compact RIO with the NI 9025 analog module.
I am able to get the signal, but too much noise.
so, how to reduce that noise, just get torque signal,
what should I used,
any filter such band pass filter or what,
any suggestion.
I am still new with the compact RIO and labview, so hope any one expert can help me
thank you
regard
MSyafiq
Attachments:
measuring torque.pdf 165 KB -
Covert analog input signal (NI 9203) to meaningful units
I'm very new to LabVIEW and I wanted to do something that I thought was fairly simple. Using the NI 9203 analog input module I wanted to measure pressure using a sensor that has an output of 4-20 mA. Altough I get some signal at the end on my screen, it's not realy the pressure. How can I convert this to a meaningful signal? I also took a look at the exeple VI's in the module specific file, but I don't have a clue how to use them.
Hopefully someone can help me out.
JurgenHi Jurgen,
You have two possibilities. But you must first know the relation between the current created by your sensor and the pressure mesured by your sensor. Normally you should receive this kind of things with your sensor.
First one, you configure the scale in MAX (Measurement and Automation eXplorer) and you can associate this scale to a task. In this case, the value you will receive in LabVIEW will be automaticly converted into the right (scaled) units. If you are not familiar with MAX and creating scales, you can take a look at this article. or the attached file or yet the MAX NI-DAQmx Help (Start >> All Programs >> National Instruments >> NI-DAQ >> NI-DAQmx Help).
Second one, you create a subVI (VI into another VI) in LabVIEW that will make the conversion in LabVIEW itself. By this way, this is simply a VI that makes the correlation between the current and the pressure.
I Hope this will help you.
Regards,
Julien Roland - District Sales Manager
NI Belgium - Technical Support
Don't forget to rate a good answer -
What are the 4 analog inputs of my umi-7764 (on the analog input terminal block)
I would like to known what are and how connect the 4 analog inputs of the anolog input terminal block of my umi-7764. I am french, so if you want to answer in french, it will be easier for me .
Sébastien,
Selon la carte de contrôle d'axe que vous utilisez (7344, 7334 ou autre), vous pouvez disposer d'entrées analogique.
Si votre carte possède des lignes analogiques (voir la documentation de celle ci), cela signifie que vous pouvez les utiliser pour 2 choses:
1. Utiliser ces lignes analogiques pour le feedback (retour en position) de vos servo moteurs. Cela veut que vous travaillez avec un servo, et que vous êtes en boucle fermé. (Pour informations, un servomoteur peut aussi asservi avec un retour en position).
2. Si vous ne faites pas d'asservissement en tension ou que vous controliez un moteur pas à pas, alors ces lignes d'entrée analogique, peuvent être utilisées comme des lignes classiques. Pour les utilisez dans ce cas, vous devez cabler
votre signal sur l'UMI (qui n'est qu'une interface entre vos signaux et la carte) de la manière suivante:
- Le point chaud du signal sur "Analog Input X"
- Le point froid du signal sur "Analog Inout Ground"
De plus si votre carte de contrôle d'axe intègre des entrées analogiques, vous pouvez configurer leur gamme dans MAX (Measurement & Automation Explorer) le range de ces voies (+/-10, +/-5, 0-5 et 0-10 V).
(Comme l'UMI est un bloc générique, assurez vous bien que votre carte possède des entrées analogiques)
Finalement, pour lire le niveau de tension sur ces entrées, il existe dans le driver NI-MOTION, la fonction "Read ADC".
sur http://www.ni.com/manuals
vous trouverez la documentation de votre matériel.
A l'adresse ci dessous, vous trouverez de l'aide concernant la configuration de votre system motion dans max:
http://zone.ni.com/devzone/conceptd.nsf/webmain/081957EE013C7A4586256B92007818E0?opendocument
Raphael TILLET
Ingénieu
r Application
NI FRANCE
Cordialement,
Raphael T -
H215 Loses the analog video signal after a few minutes after start up.
After Windows 7 is loaded and about 30 minutes to an hour of normal screen and computer usage, the display goes black and my Viewsonic monitor says that the analog signal is missing and then goes into power save mode. Why is this happening? And the only way to resume the use of the computer is to force shut down the tower and then to power it back on. Which then runs through the failed start because I had to force shut down the system due to the display losing its signal. Please assist in this matter. I just bought the system a few days ago and for it to be doing this is quite dissatisfying. Thanks.
The system specs is:
CPU: AX2 250
RAM: 4GB
HDD: 1 TB
ODD: DVD-RW
OS: WIN 7 HP
D4RK51D3 G.F.X. LLC
Engineering the 1337 way.Hello Oremus Productions,
First of all, sorry for this frustrating issue. The first thing to check with OS X Mavericks or Yosemite is the permissions of your Adobe folders. Here is blog post to check out: Premiere Pro CC, CC 2014, or 2014.1 freezing on startup or crashing while working (Mac OS X 10.9, and later)
The other thing I'm curious about is ProRes and if Premiere is handling it properly. Tell me, do you have Final Cut Pro 7, Final Cut Pro X, iMovie, or any of the Apple video products installed? Do you have any components in your Mac HD > Library > QuickTime?
Thanks,
Kevin -
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 KBShiva;
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 -
How can I measure the frequencies of two analog input signals simultaneously?
Hi
I have two AI signals, and I need to determine the frequencies of those signals. The frequencies range from 1-125Hz. I currently have a VI where I can sample one of the signals for 1 second (sampling at 300 Hz for 300 samples) and determine the frequency.
I need to read two signals at the same time and get both of the frequencies at the same time, but I can only figure out how to read them individually, so I can read one signal, then one second later I read the second one, then I read the first one again, then the sceond one, etc.. How can I read two signals simultaneously?
Thanks
Attachments:
FreqMeas11.vi 41 KB
FreqMeas11.PNG 18 KB"at same time", this depends on the hardware, you can do as has been previously stated just set up a 2 channel acquisition and you will get 2 sampled waveforms back. Most hardware A/D as multiplexed and true simultaneous sampling is not done. At 125Hz this is not an issue unless you are interested in very small phase changes between the samples. just keep this in mind if you are expecting samples to be completly synchronized.
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA -
I have added a vi, but it doesn't quite work. Would be very grateful if someone could help, thanks!
Attachments:
Average_0411041_2.vi 77 KBThe attached VI collects 100 ms of data and does a rolling average. Since your sub-VI were not included I created this from scratch. There are comments in the code. I hope this is what you need.
Dirk
Attachments:
rollingaverage110x100.vi 47 KB -
Multiplexi​ng channels after the analog inputs of a DAQ Hardware
Hi,
I need to sample a 5KHz analog signal with 48 channels.
It's needed all these channels simultaneos.
I know there is not a DAQ hardwere at NI beyond 4 simultaneos channels.
How could I or NI solve this problem? Have NI an hardware that could be applied?Greetings,
You are correct in that there are no simultaneous sampling boards that have more than 4 channels. Performing truely simultaneous sampling will ensure that there is virtually no interchannel delay and that the phase relationship between each signal is retained. If you use a regular Multifunction Input/Output DAQ board and some sort of signal conditioning, like SCXI, to increase your channel count, you will be performing a multiplexed operation. However, in most cases the interchannel delay is on the order of microseconds. If this is still too much for your application then I'm affraid the only answer is to get multiple Simultaneous Sample boards. You would want to trigger each board's acquisition to start at the exact same time. In order to
do this you could either use a PXI system or use PCI and leverage RTSI.
However, even with this suggestion you should keep in mind that most PCs only have 5 PCI slots, which will limit you to 5 * 4 = 20 channels. If you went with a PXI system and used the PXI-1006 chassis, which has 18 slots, then you could fill it with 12 PXI simultaneous sample cards.
PXI
http://sine.ni.com/apps/we/nioc.vp?cid=1525〈=US
NI PXI-1006
http://sine.ni.com/apps/we/nioc.vp?cid=4889〈=US
S Series Multifunction DAQ
http://sine.ni.com/apps/we/nioc.vp?cid=10834〈=US
Regards,
Justin Britten
Applications Engineer
National Instruments
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