Analog voltage control

Similar Questions

• Generate an analog voltage with amplitude variations

  I want to generate a 0 - 5V analog voltage output that has a variable amplitude, as shown in the figure. The maximum voltage is 5V and low voltage a percentage of this, but I must not vary the amplitude during execution of VI.

  

  With digital outputs, you are limited to two levels. Low and High. (1 and 0). Here are the outputs of the DIO lines as DC voltage levels. The two levels can be anything, but 0v is most commonly used for bass and 5v is used for the great. This is called (as well as some other features) TTL logic.

  There are some cards that allow you to choose the digital voltage levels, but your all-in-one does not provide this functionality.

  You could do something similar with digital, where you have only used the 0v and 5v levels.

  You are absolutely right that software control timing is less precise than the timing control material, however, if you did a spot of digital output in this way and set it up to do the finished samples or continuous, it would use a material timing and would therefore be very accurate (in accordance with the specifications in the technical data of the device).

• How can I create a single delayed output (analog voltage) of a Trigger (analog voltage) input reference pulse?

  I am working with a combustion chamber and using a system of data acquisition (with the hardware OR SCB - 68) to read the pressure in the cylinder (such as analog voltage). I'm trying a pulse delayed, 1 millisecond to 5 volts of output once the pressure in the cylinder is high above 5 bar (which corresponds to an analogue voltage of 0.25 V). I would also like to record 30 ms samples before the trigger and 220 ms samples after the outbreak. The following image shows visually what I'm talking about.

  I created a LabVIEW VI (which is attached), but I keep running into 2 issues:

  1. When I run with samples finished after a period of time, I get error-200281which I don't quite understand.
  
  
  2. Using the Express VI 'Out of time' to keep time for the pulse I can not get a resolution of 1 millisecond, the pulse is not generated when I put the window between 0.003 and 0.004 seconds for high pulse (i.e. the resolution of 'Elapsed Time' seems to be too coarse).

  I'm a beginner to LabVIEW sorry if my questions are trivial or my VI makes no sense, but I was stuck on this during more than a week. Any help would be greatly appreciated!

  Thank you

  Morgen

  This isn't a good way to trigger a pulse.
  Use a trigger DAQmx to send the pulse when your acquired signal exceeds 250 mV you specified.

  See this for DAQmx trigger:

  http://www.NI.com/white-paper/2835/en/#toc4

• How to acquire and store the values of DAQmx analog voltage (I do not want the graphic, but strings and values in a chart)?

  Hello

  How acquire and store the values of voltage DAQmx?

  I tried several code example, but they can't get the chart. I don't want to chart. I want to measure exactly the analog voltage values and record these values - as an excel chart, that contains the selected channels and voltage values.

  What the example code that I can use?

  My hardware is NI PCI-6251.

  Thank you very much.

  
  

• Get the duty cycle of DAQ to analog voltage input module

  Hello.

  I'm new to labview. I have an analog voltage input data acquisition module. I try to get the duty cycle of a square (generated from a function generator). What is the best way to go about this? When I use the vi to acquire an analog wave cyclical report, the values are incorrect.

  Post your VI as well as real data of your signals so we can see what is happening.

  Lynn

• "The analog output control.

  I am newbie in Labview... and it is very difficult to find good help and tutorials... it's really disappointing.

  I want to find a good simple example of 'the analog output control "...

  I found these 'words' somewhere on the internet in the file 'DAQBasic.pdf '.

  It is mentioned I need 'VI' easy, but I can't find something like 'Easy VI' in the functions available.

  There is far too much info anywhere and there is no structure...

  How can I 'the analog output control "?

  And please, I want simple examples...

  Thank you!

  Why spoil things by connecting the key to something?

  Your code should be close to what you asked. You want to make sure that there is no case of timeout. I would use the event to change value instead of the key down. At startup, the acquisition of data code run once and then after that, wait key. A couple of different ways to fix this. Simply place the code for the acquisition of data inside the event.

• is it ok to connect two outputs analog voltage in series?

  Ok... I have a PS-210 FieldPoint... basically an analog voltage output 0 - 10V, 200mA per channel (with additional external power supply)... my question is... can I plug two channels in series?  Love how I can put two AA batteries in the series... and then to double my blood pressure?  and then check my two separate channels and the sum of the tensions would be assujettirait I have my load in?

  Thank you!

  No, you can't.  The channels all share the common side of their outputs.  If you've tried to hang them in the series, you have wind of short-circuit one output from the ground.

  The reason for which you can do with batteries is that the tensions are floating.  There is no common reference between the negative terminals of both batteries.

• Trigger SW analog voltage CONT Acq & graphic

  Hello

  In the example Cont Acq & chart analog voltage SW Trigger.vi It seems to me that if specify you a channel that relaxation comes on, then it would be a hardware trigger is not a software trigger. Why do call it a software trigger work?

  I PCI6071E I want to trigger by sending in a channel if a pulse (63). Wouldn't that considered triggering material? If that is an example for this available?

  Also I'm not clear on what they mean by the parameter ' Amplitude/hysteresis window' in the trip parameters. Could someone explain this to me?

  Thank you!

  
  

• NEITHER 9234 with quasi static analog voltage

  Hello

  I have a NI 9234 (4 channels + / IEPE 24-bit 5V) attached to a chassis cRIO module. This module is ideal for accelerometers and microphones where the tension is in constant evolution (ie; measures of variation rates).

  I also have a module OR 9237 (4 channels 24-bit full-bridge module analog input) attached to the same cRIO. This module is ideal for measure variable voltages of strain gauges (quasi static and dynamic loads).

  The attached graph shows the two channels, collected synchronously, but as you can see the (red trace) cell breaks down (as it should), but then drifts back to zero on its own, when in fact it should remain low just like the extensometer is beam. After all, the two sensors are physically secured.

  Q1: Would that have something to do with AC/DC module 9234 internal coupling?

  Q2: Is it really possible to collect "quasi static" ongoing tensions by using a NI 9234 module?

  No explanation as to why this occurs, or if there is a way to remedy this would be appreciated.

  Kind regards

  Andreas

  Coupling AC/DC must do a lot with your question. In mode AC voltages static will be fitered outside and the 9234 measure indeed only change voltages. In DC mode, the voltage goes directly to the AD converter and you can also detect static tensions.

  A minute of Googling gave me the answer, this load cell electric piezo can measure dynamic changes, as any charge will escape the path the lowest resistance and the signal will go to zero after a certain time. I guess the other device you were using higher internal resistance (which is relatively low on the 9234), so it takes more time to what he flees, but he also took on the picture you attached your second try.

  Here you can find more example under the title

  "WHY ONLY DYNAMIC FORCE CAN BE MEASURED WITH SENSORS OF POWER PIEZOELECTRIC"

  http://www.PCB.com/techsupport/tech_force

  Andreas Jost

  Technical sales engineer

  National Instruments

• How to create the ampere control signal (4-20 my) of the voltage control signal (- 10 - 10 V)

  I must control 4 proportional valves (Bürkert 2873 x 3 & 2875 x 1) installed on a gas pipeline. These type of valve control signal is 4-20 my. I have a data acquisition NI USB - 6343 with 4 AOs of V-10-10 X. How can I control these valves with the DAQ hardware? I am not familiar with ELECTRIC/ELECTRONIC, that is why I ask. Thanks in advance.

  This device can produce only 5mA on the analog output.  So, you will need an op amp that can display on your 20mA.  See here for the creation of a converter with an op-amp circuit.  Your USB-6343 should provide 1 to 5V to the op-amp.

• Blocking of blue screen with the analog voltage (WinXP, PCI-6251)

  Hello

  I'm looking to solve a problem of blue screen with my measure blocking
  application, which I am developing with C++. Blocking seems manifest
  a little random after a variable amount (500-50 000) of voltage analog
  measures. My application needs to make a huge amount of these digitally
  trigger voltage measures after a certain period of time, and I'm using a
  unique
  task to do. The task is stopped and started after a single measure
  is
  which is done around 10 000 - 100 000 times per second. For this
  because I do synchronized with the PCI-6251 map data acquisition and
  one
  Ztec oscilloscope card. It seems that the probability of blocking could be
  associated with
  the frequency of measurements of voltage that I perform.

  The
  the app itself is multithreaded, but I'm blocking concurrent access
  TO
  the card with lock - all access to the card are behind a single mutex

  lock, so simultaneous access is blocked. In any case, all data acquisition
  access
  o the map is initially a single thread, which is dedicated to the acquisition of data
  operations.

  I also did stress tests with Ztec scope map, which does not
  result
  in all the problems. I also disabled in order of acquisition of Ztec map data
  TO
  Make sure that it wasn't the card scope, the origin of the problems - the problem
  persistent, so this seems to point towards the direction of the nidaq map.

  The deadlock appeared when I used the original supplied with drivers
  the
  card. I installed the latest drivers (removed the device from)
  ' Windows
  Device Manager and your application Measurement & Automation, reinstalled), but the blue screen still appears.

  Blue screen gives me a few debug data, but it does not mention any

  files .dll or something that would be of course point to a specific file (driver). I enclose at least partially matching code snippets.

  Hello again! I've been in contact with a local support person, who suggested that I have use DAQmx_Val_FiniteSamps instead of DAQmx_Val_HWTimedSinglePoint. I don't have any other changes, but this (see below) and the problem disappeared, so this seems to be an acceptable solution, because I don't see at all why not do this way. (Thanks Henry!)

  DAQmxErrChk (DAQmxCfgSampClkTiming (task_reader, NULL, 100000.0, DAQmx_Val_Rising, DAQmx_Val_HWTimedSinglePoint, 1));
  DAQmxErrChk (DAQmxCfgSampClkTiming (task_reader, NULL, 100000.0, DAQmx_Val_Rising, DAQmx_Val_FiniteSamps, 2));

• Sampling motion controller analog voltage (from a load cell)

  
  

  Dear nstroud,

  Or the other of these commissions should work for you. You can configure one of the axes for engines step by step closed loop analog feedback and then put in place the other 2 axes as slaves to the first with a debt ratio of 1 to 1. This would cause all 3 of your axes to behave in the exact same way. This transmission is made on the card, and you should not see any negative impact on the axes update rates. The specified sampling rate should not be a problem either. The update of control loop period is definable in the adjustment of the loop tab, and for stepper motor axes, it determines how ofter the step generator is updated. The default for this value is 250 milliseconds. The 7340 user manual also lists the scanning speed of demultiplexer of analog input @ channel 25 microseconds / activated.

  So you would be actually sampling and update the engine generator step much faster than 100 Hz with analog feedback on axis controllers.

  See this knowledge base for more information about the configuration:

  Analog feedback with a stepper motor:
  http://digital.NI.com/public.nsf/allkb/AB3CCA7FBFAD749A8625713B001D8581?OpenDocument

  Best regards

  ~ Nate

• Analog voltage trigger

  I'm using LabVIEW 7 on windows 2000 with the PXI-4461

  I'm trying to have the labview read arriving through the analog input voltage but start recording data when the voltage passes a certain threshold value. I tried an example 'acquisition & graph continuous tension - analog trig SW. The graph displays amplitude on samples. I am looking for amplitude over time. Any help is greatly appreciated.

  Thank you

  SparkEE

  No, it is not necessary to a xy chart. A normal graph displays a signal sampled regularly with time on the x-axis if you configure the properties of the graph for absolute time or regular. If you buy a type of waveform data, the chart uses the t0 and dt signals. Right-click on the chart and do of course ignore timestamp is not selected.

• Source of voltage controlled blow - once

  Hello

  How can I set the width of the pulses produced by the one-shots-controlled voltage source? Place IWant to 0.4 sec

  Thanks in advance,

  10CHAR.

• measurement of analog voltage tends to zero

  Hello, I'm new to the forum see lab and Labview FPGA. First of all I would like to describe my system: I measure the voltage of the voltage inverteres-three with LEM - LV 25-400. Three analog inputs (I + and HAVE-) are connected to the LEM. I run the analog measurement of Labview demo program and it can measure the voltage, but donot values remain constant. He goes to zero and after some time goes to the correct value. My blood pressure never goe to zero. One can derive a little but almost constant. If I add the filter with high sampling rate, I had an almost constant value but miss the ripple values. I wonder if anyone can help me would be greatly appreciated.

  with respect,

  Marco

  problem solved