Threshold voltage

Similar Questions

• Threshold voltage DAQ for awhile

  Hello

  As a newbie to Labview, I find it a bit hard to make a difference.  Here's what I want: I the acquisition of values of voltage from a source of power through the acquisition of data in a while loop. Once the sections of tension, say 4.8V, I want to stay above the 4.8V for a specified period, say 5 seconds. If so, I'll file an action. Until this is the case, I will keep sampling values. I had a look at a few examples, but none of them not what I intend to do. . Can someone also tell me where I need to look for similar issues in the future?

  Don't not to argue with mike (which is much better than me), but here's how I would do it... where the vi to take data is where you get your data...

  -Matt

• How to determine the threshold for an LED voltage

  A density of current over voltage that is generated by one of my Labview OLED measurement systems is attached.  I'm trying to programmatically determine the threshold voltage.  When the data is displayed in the logarithmic scale it is possible to observe a charge injection clear (0.8, 0.000203).  The problem is that I can visually observe this value, but I'm not able to solve by program for her.  I tried to take the derivative to observe the changes of slope, but only to determine the operating voltage.  Any ideas how I could solve this value?

  Thank you

  E

  You are on the right track, you just have to do deeper. Try to take the 2nd derivative and find the points where it is larger. This will show you where the log graph is concave upward and where is your ve. I've included a plot of Log (data), D (Log (data) and D (Log (Data), 2).) I also have zoomed in on the area of interest, then pay attention to the balance.

  You may need to make some good assumptions. For example, with exactly what I posted above, you get Vth = - 0.4 or so. If you assume Ve > 0, then you get Vth = 0.8.

  In addition, you probably want to do other fancy stuff such as: interpolate the data to get more points, smooth interpolation, trim the ends of the derived data (they want 0 according to your derived method).

  

  

• Help the spikes of voltage high frequency Counting

  Equipment: NOR USB-6229 (250 ksps / s analog in., 16 bit DAC, 32-bit counters, and internal clocks)<= 80="">

  LabView 14

  Problem:

  I have an experimental app where I need to count the points of tension (entire #) caused by electrons striking a sensor. These tips can be as frequent as 500 000 heads of charge/sec. The tips aren't going to be the same tension every time, but they will be visible above the noise, so I need allow the user to select a threshold voltage that triggers a true count rather than the tips of noise.

  Attempts:

  To count such a high frequency, I gather that I need to use a counter entry to read fast enough, HOWEVER, I wasn't able to find a way to define a threshold of voltage for a counter entry because I think they expect a TTL signal anyway, which I won't. To set the threshold, I realize reading of analog input can be triggered at a point chosen, which is great, but the Analog Input sampling rate is only 250 kech. / who will not catch count each in my project.

  I have a program that uses the channel count edges and it is accurate to 3% of the # expected charges. I was looking at him just with a function generator and the program does not count unless the signal voltage is higher than V 2-3 who does not work for my application. I'll post what I have. Someone know how to trigger at certain levels of tension using counters, or know a way to filter through the noise to get real tips?

  Thank you!

  You will need a device with a sampling rate of greater than 1 MHz analog input or you will need an external reference. With the external comparator, you can use output to set the threshold, although the user would not be able to see the signal or the threshold, only the analog account result.

  Lynn

• measure the tension between adjustable borders

  Hello

  For my program, which I use to read temperatures and flows, and etc., on an engine test bench, I want to be able to build in a sort of borders of adjustable threshold for the minimum and maximum values for the tensions. When the engine is not running, there are still some low floating values visible on the façade. I want to put in a few border/threshold voltage values. This value should leave the front panel displays to display zero when the signal is very weak and floating. Is there a function for this? For ceilings, it is not really local, but I wonder if there is a building block for this already present in labview.

  My program should also be attached.

  Thanks in advance, best regards, Theo

  Is that what you want for your noise suppression? It uses the range and force? to test the signal against the limits and replaces everything off of the beach with zero data.

  Lynn

• Two subsequent acquisitions - 2 does not work

  Hello

  Here are the main features of my configuration:

  1. Two channels of generation/acquisition
  2. Each channel was part of generation (staircase varying low) and acquisition (output is shorted at the entrance)
  3. When the output value reached a threshold, stairs stops and last tension remains in the output
  4. The behavior of two Channels are identical, the only difference - the value of a threshold voltage
  5. And finally the most important feature - channel 2 should run once stops 1 channel

  The VI is organized as follows:

  1. Outer loop that should run 2 times - it starts with the 1st string and then should run with 2nd channel
  2. The FOR loop variable 'i' controls:
     • "source" and "sink" for the execution of channel
     • choice of the threshold
     • local variable (which stops staicase) choice
     • indicator for the performance of channel

  The problem is: 2nd iteration of the outside OF the loop does not run.

  Where I've been misled?

  Thanks in advance

  Pavel

  Hi Pavel,

  When the 2nd iteration of the loop FOR external it starts no way the 1st iteration is not yet complete. THINK THE STREAM!

  Have you checked that the behavior to help highlight the debug execution? Where your loop IS blocked?

  Edit: I see now where your 1st iteration gets stucked - even without executing the code!

  Please check all THE terms of judgment of your inner loops: one of them will never stop in the 1st round of your outer loop!

• The data in a loop of consumption does not evolve

  Help!

  I am reading different voltage to an interval of 500ms in a loop of producer and move to the consumption loop. However, I notice that the values in the loop of the consumer do not change even when the voltage has changed?

  What can I do?

  You're probably stuck in inner loops. Given that the value of the voltage of the capacitor is powered in from out of the loop, this value will be used only inside the selection loop until the loop stops running. Thus, if the first capacitor voltage is lower than the upper threshold voltage, then the inner loop in the load case will never end.

  You don't need the inner loops at all. You want to test against thresholds exactly once for each reading of the voltage. The lead of the comparison to a case structure. If the condition is true, write to the output channel and change the State. Otherwise, do not write and return to the same State on the next reading.

  Another thing. When you stop the program, you can set the output before close so your capacitors do not sit it loads.

  Lynn

• How do 9229 trigger by analysis of data

  Since 9229 (USB casing) has no external analog trigger; the signal lasts 12 seconds.

  I need to scan data collection the long, until the trigger threshold voltage is detected, then beginning to collect 12 seconds signal.

  But after the detection threshold, some data may already lost when the start of collection time 12 seconds.

  Also ' How do make a scan ", the scan to read th data should be in a loop. If set the duration for each big loop, then maybe the loss of data, but if too samll, then can make the Windows.

  Any suggestion how to read the analysis of data from the device. Thank you.

  Hi Turbot,

  You can just continuously sample and store the data in the table.

  If the size of the data is greater than 12 second pad just outside, and the threshold is reached, use the subset of table data to select just 12 second part.

  You can see my attached sample for more information.

  Sincerely, Kate

• Once when a structure deal is real in a while loop

  Hello. The first time post here to forgive me. I tried looking for answers in the forums, as well as to try the solution myself, but nothing helped.

  That is the problem. I'm currently collecting signals of tension using the DAQ assistant. When a certain threshold voltage is reached, the 'real' case would go. I am currently using the shift with the while loop register so the number of output "digital 2" would be like while running in a loop. However, I want to only register a single case that long voltage above is greater than the threshold.

  For example. When the voltage is greater than 3V for awhile, he recorded only 1. Then the tension could plunge 3V. The next time that the voltage is above 3V again he would record a 2. So on and so forth. I have attached a picture of my diagram below. Thanks for the help!

  

  Keep the status of the threshold is reached in a record time difference.  Run an AND with the inverse of the value in the shift register and your new threshold detection.  The result of the AND goes into the structure of your business.

  EDIT: I just threw this example together.  I used a feedback node, because it would be cleaner.

  

• stop the program

  Hello

  I have a programworking of labview as follows

  the labview program will wait you until the threshold is detected as if the voltage is greater than 5 volts

  then it will send an sms message using a modem gsm per VISA

  the threshold voltage can last for hours and I don't want that a message be sent while the program is always looking for amplifiers

  I need the prgram to run all the time that I need to watch the House through labview

  So what program I can do

  I think its simple, but I can't reach it

  looking for your help

  

  To detect the transition that you want to look for the case where the current value of the comparison to the threshold is in a State, and the previous comparison is in the other State.

  You should have a wait in the case of False function (or a single outside the structure to deal with values inside each case). Without it, the loop runs as fast as possible to consume all of the CPU resources available at least in a carrot.

  Is there a reason that you have three written rather than the concatenation of all the channels and just do an entry?  Normally, opening and closing the serial port inside a loop are not a good idea.  You indicated that the system may be inactive for hours between messages, so it may be OK here.  What happens if the serial port configuration fails because another program is using it or the GSM device is unresponsive?  You do not any management mistakes.  A remote system running for long times should have robust error management.

  Lynn

  

• % SFF8472-5-THRESHOLD_VIOLATION: RX

  Hi all

  I have this problem on 2 4503E switch

  CORE01

  % SFF8472-5-THRESHOLD_VIOLATION: 1/Te1: low power warning Rx; Running value:-13,8 dBm, threshold value:-9,9 dBm.

  % SFF8472-5-THRESHOLD_VIOLATION: 1/Te1: low current alarm Rx; Running value:-13.9 dBm, threshold value: d - 13, 90 dBm.

  4503E_CORE01 #sh transceiver interfaces

  Optical optics

  Temperature Tx Rx power supply voltage

  Port (Celsius) (Volts) (dBm) (dBm)

  ---------  -----------  -------  --------  --------

  TE1/1 23.9 3.26-2.2-14.0

  4503E_CORE01 #show inte te1/1 trans det

  Alarm high high low warn warn low alarm

  Temperature threshold threshold threshold threshold

  Port (Celsius) (c) (c) (c) (c)

  --------- ------------------  ----------  ---------  ---------  ---------

  TE1/1 24.1 75.0 70.0 0.0-5,0

  Alarm high high low warn warn low alarm

  Threshold voltage threshold threshold threshold

  Port (v) (v) (v) (v) (v)

  ---------  ---------------    ----------  ---------  ---------  ---------

  TE1/1 3.26 3.60 3.50 3.10 3.00

  Optical alarm warn high low warn low alarm

  Transmitting power threshold threshold threshold threshold

  Port (dBm) (dBm) (dBm) (dBm) (dBm)

  ---------  -----------------  ----------  ---------  ---------  ---------

  TE1/1-2, 2-1, 6 1,3-7,3-11.3

  Optical alarm warn high low warn low alarm

  Receive the power threshold threshold threshold threshold

  Port (dBm) (dBm) (dBm) (dBm) (dBm)

  -------    -----------------  ----------  ---------  ---------  ---------

  TE1/1-13, 9-1, 9 1.0-9.9-13.9

  CORE02

  % SFF8472-5-THRESHOLD_VIOLATION: 1/Te1: low power warning Rx; Running value:-13,5 dBm, threshold value:-9,9 dBm.

  % SFF8472-5-THRESHOLD_VIOLATION: 1/Te1: low power warning Rx; Running value:-13,5 dBm, threshold value:-9,9 dBm.

  4503E_CORE02 #sh transceiver interfaces

  Optical optics

  Temperature Tx Rx power supply voltage

  Port (Celsius) (Volts) (dBm) (dBm)

  ---------  -----------  -------  --------  --------

  TE1/1 27.5 3.24-2.3-13.5

  4503E_CORE02 #show inte te1/1 trans det

  Alarm high high low warn warn low alarm

  Temperature threshold threshold threshold threshold

  Port (Celsius) (c) (c) (c) (c)

  --------- ------------------  ----------  ---------  ---------  ---------

  TE1/1 75.0 27.4 70.0 0.0-5,0

  Alarm high high low warn warn low alarm

  Threshold voltage threshold threshold threshold

  Port (v) (v) (v) (v) (v)

  ---------  ---------------    ----------  ---------  ---------  ---------

  TE1/1 3.24 3.60 3.50 3.10 3.00

  Optical alarm warn high low warn low alarm

  Transmitting power threshold threshold threshold threshold

  Port (dBm) (dBm) (dBm) (dBm) (dBm)

  ---------  -----------------  ----------  ---------  ---------  ---------

  TE1/1-2, 1-1, 6 1,3-7,3-11.3

  Optical alarm warn high low warn low alarm

  Receive the power threshold threshold threshold threshold

  Port (dBm) (dBm) (dBm) (dBm) (dBm)

  -------    -----------------  ----------  ---------  ---------  ---------

  TE1/1-13, 5-1, 9 1.0-9.9-13.9

  I have only 1 transmitter/receiver on the two switch, I changed the cord fiber also the same question.

  Hello

  Yes, for positions that are in place and functioning, there is no work around that I know and who have not been able to get a good response from Cisco, but they insist it is a cosmetic error message.

  can sometimes replace the SFP, but the error comes back again.

  You can open a ticket with TAC.  They have a work around in the newer versions.

  HTH

• How to start a timer in labview, when a signal crosses a threshold of voltage

  Hello

  Please could someone help to find a way to start a timer when an event occurs? (like when a signal crosses a threshold of voltage)

  Thus, I would ask that help me cope with the following question:

  I'm acquiring a signal from an acquisition of data and comparing it with a certain threshold value. Once the voltage of the signal crosses this value, a timer should start and will continue until 30 seconds, IF the signal value PERSISTS beyond the threshold. The timer must be set back to zero if the voltage of the signal goes back the threshold before a period of 30 seconds.

  Thanks in advance for your support,

  Bill

  Hi Bill,

  What version of LabVIEW are you using?  If you are in 2009, you can actually save the .png to your computer file and just drag it into the block diagram of a white VI.  Also attached is the VI even recorded in LV 8.2 (the feedback node has been replaced with a shift during the downconversion register).

  Best regards

• An event cannot be on the threshold of voltage

  I am collecting and drawing a tension unique channel and must have a break in the proceedings until the tension goes back to a certain threshold.  I made a loop as shown below that I think will work, but it feels weird I have a continuous playback in a loop - wouldn't be reading some other function?  Is it possible to use DAQmx Edge if I'm NOT trigger measure?  I'm new to labview and don't know if there is a more common way for what I think is a frequent task.

  Thank you!

  Research in the specifications of this device, it seems as if she has no redeclenchables tasks available to it. However, when I saw the application, it seems you do not seek to collect DAQmx data all the time, but rather use it to trigger the State of your state machine architecture. For this kind of application, what you have seems to be a nice way to compare values.

  However, I have noticed that your DAQmx task continues to run for other States. This may cause the DAQ hardware buffer overflow because it does not read all the time. I recommend starting the task just before that you will need to check and then stop the task before moving on to the next State. This will decrease the load on your DAQ hardware, so as to avoid some errors to occur.

• 6009OEM output voltage and current

  Hi all

  Just try to make sense:

  http://www.NI.com/PDF/products/us/20043762301101dlr.PDF

  Page 3 says: high output voltage (push - pull, I = - 8.5 my) = minimum voltage 2.0 v maximum voltage = 3.5V but where can I find out what current can it provide and continue to produce an output voltage more than 4.2V?  (4, 2V is the worst case for the high threshold of logic of a chip, I want to control).

  Thank you!

  J

  Hello J,

  As you mentioned is the maximum voltage of 3.5V when you have a high output voltage (push - pull, I = - 8.5 my). If you need more than 3.5V then you might need to change to an open-drain output. As you can see from the link you provided that you would receive a maximum voltage of 5V.

  If you do not use an open-drain output you have to combine with a pull up resistor.

  I hope this helps.

• Controlled by the voltage analogue output

  I missed more or less in my attempts to use the analog output features DAQmx.  What I want to do is to create a program that will spend the next an analog input channel voltage analogue output channel.  The basic idea is this: I am able the differential voltage in a simple temperature detection circuit.  When tension crosses a threshold (for example, 2, 5V), analog output channel kicks on a constant 5V and stop to expel 5V when the tension of AI cross back on 2, 5V threshold.  Is it still possible? I had trouble finding examples or starters to tide me over.  Any suggestion would be appreciated. Write the code to acquire the signal of the AI is not a problem, I'm not sure of how to integrate the functionality of the ao.

  Thank you.

  Unfortunately I do not have libraries of Measurement Computing, so I really don't see what you're doing with your code, but I'll attach one VI example I did with DAQmx to get going you, and I hope that thinking in the right direction. I've added the analog out and digital output to show how each works. If you can make your code in DAQmx, please do and post and I can help you.