I am trying to acquire pulse signal (TTL 0 ,+5v) using parallel port (SPP 25 pins) on pin 12.

The state register adress is 379h. When I run continuously this VI, the value diplays 78 and 58 periodycally.
I think that 0 correponds to 58 and +5v correponds 78. Is this correct ?
So my questions are:
1) How can I do to read only pin 12.
2) How can I do to display graph of a pulse signal (TTL 0 +5v) from value.
I attached the I am using.
Thank you in advance.

pin 12 is bit 5(32 decimal) of the byte you read from port 379h. So actually 58 is +5V and 78 is 0V.
in C:
if(32 & data){
/* pin 12 is high (+5V) */
} else {
/* pin 12 is low (0V) */
graphing depends on your programming language and tools available.
If your signal is slow enough, and you don't need very good accuarcy, use a software timer and get a measurement every x mS

Similar Messages

Suggestions to improve the filter output of the acquired pulse signal

Hello,
I am working with acquiring the pulse signals form DAQ using a sample rate of 1k and number of samples as 1k for every 1sec signal using the DAQ.
I am using the smoothing type filter with Moving average->Rectangular->Halfwidth=3 and passing the smoothed signal to the butterworth filter with my requirements of 2.3hz and 0.7 with sample rate of 1000.
Problem:The filtered signal is always starting form 0 instead to start with the first value in the acquired pulse signal.For example, starting from 0 instead to start from around 0.057 as shown in the images.
How to make the filtered signal to start from the original pulse signal value.
Thanks in Advance.
Attachments:
improvementinfilter.jpg ‏164 KB

All filters have a transient response. A bandpass filter with a DC component at the input will have that transient strongly excited.
Some of the filter VIs have an Init? input. If the signal is continuous but is being filtered in segments, that input can help by retaining the previous state of the filter. The first transient will still be there, but later ones should be erduced or eliminated.
In the example VI attached you will find that there is a transient at the beginning of each segment. This is due to the sine signal not having an integer number of cycles.
The IIR Cascade Filter with I.C.vi and IIR Filter with I.C.vi in the Signal Processing >> Filters >> Advanced IIR Filtering palette have an initial state input.That might be helpful but calculating an appropriate set of initial conditions from the signal data may not be straightforward.
What do you want the output to look like? What are you doing with the filtered data? Perhaps there is a better approach than a filter.
Lynn
Attachments:
Filter transient.vi ‏19 KB

How to acquire analog signal and send a TTL pulse at the same time based on PXI 6123

Hi,
I am using a PXI-6123 data acquisition card, as the picture show in the attachment ,I want to acquire the analog signal of ai0 through reference analog window and at the same time send a TTL signal to trigger my camera. I have tried two methods, one is using the DAQmx Export signal.vi another is using DAQmx connect terminals, but when the data acquisition card acquire the analog signal, the DAQmx Export signal.vi and the DAQmx connect terminals sometime can send an TTL pulse ,sometime can not.
I don’t know why? or some other method that can achieve my arm is appreciated.
Regards
chunlei
Attachments:
method export signal.vi ‏21 KB
method connect terminal.vi ‏36 KB
Send a TTL pulse.JPG ‏288 KB

Hi,
Have things changed over the years?
I need to syncronise a digital output (Modul NI9474) and an analoge input (AI-Modul NI9203) module. I need to measure time intervals from a flank in signal A to a flank in signal B. I would like accuracies of the order of 1 ms. Currently, the signals are not synchronised, with errors of the order of 2 times the block length (block size x sample rate), sometimes much higher. The best I got so far was a block size of around 20 with a sample rate of 1 kHz.
If I use the master and slave settings on the RTSL settings, my program doesn't run properly.
If I use digital signals for input and output, I can syncronise them with RTSL settings and everything is good, but I can't always do that.
Also, if I do anything in the GUI (such as scrollowing something or going to another window), my output gets screwed up properly.
1. What can be done to synchronise AI with DO?
2. Is there something that can be done to avoid messing up the output when something happens in the user interface? (I know that I am messing up the outputs as they make some valves switch and that is loud).
Thanks in advance!

Wiring a SCB-68 to measure the frequency of a TTL pulse signal

Sorry if this is a basic question but could someone please help me and tell me how to wire up a SCB-68 connector block (connected to a AT-MIO-16 DAQ board) so that I can measure the frequency count of a series TTL pulses (signal from photon counting). At the moment I don't understand how the PFI1-9 connections are related to the GPCTR0/GPTR1 counter connections on the block and how they're all realted to the source,gate and out 1-5 connections on the DAQ board.
Ultimately I want to be able to put this measured frequency into a Labview program with a controllable gate period.
Thanks in advance
Nick

You might want to search the Knowledge Base on the NI's Support Pages for "Cable Mapping for a 68 Pin Connector to a 50 Pin Connector". This should take you to a link that will explain the mapping of a 50way to 68way cable and subsequent lines you are looking for ( reference sub link 68F50M), I guess you have SH6850 cable connected from the AT-MIO16 card to the SCB-68.
Please check out the information about the pin outs, that should help you work out which pins map to the counters, eg GPCTR0_source would be pin 37 on your SCB-68
Regards
Joe (NI)

Ramping a pulse signal using PCI-6602 card

I'm controlling a stepper motor and need a continuous pulse output with variable frequency. I need to accelerate and decelerate teh motor (It can't start immediately at a high frequency but needs to be ramped up to it). I can't have any hiccups in the signal or the motor can stall. It seemed I had my own ramp program written (which gradually increased the frequency value sent to the counter) to solve this problem, but when I switched to Office2000 I started getting hiccups in my signal. I also have a PCI 1200 card and could use A/O but I think using the counter signals would be better. If I'm wrong let me know. Once I have the motor up to speed I am reading in a pulse signal to analyze with FFT.
thanks for y
our help.

A few thoughts & musings, hope some of them are useful:
1. The sequence for setting a new frequency should be to first load up the new pulse specs (use 1 & 2, not 3 & 4), then issue the "switch cycle" command to 'Counter Control.vi' You can look at NI's example program called 'Pulse Width Modulator' to verify syntax.
2. If your frequencies are low enough and your loop time is fast enough, you may be trying to update the pulse specs before the previous specs have completed a full cycle. This has traditionally been a no-no, though I'm not 100% sure that it remains one with the latest NI-DAQ drivers.
3. No ideas about the possible interaction with MS Windows and/or Office 2000. Haven't used either.
4. (My own latest installment in a multi-year running gripe at NI): Wh
en oh when will we be granted the ability to perform buffered counter OUTPUT operations? Just as in the analog world, one can acquire a signal with AI and then reproduce it with AO, it would be REALLY REALLY handy in the counter world to measure with buffered semi-periods and then reproduce the same pulse train with a buffered output.

How generate/acquire pulse andacquire image simultaneously?

HI
I have:
PCI 6251M to acquire data
PCI 1427 (to acquire image with camera uniq UF1000)
Labview 8.00
Frame grabber BNC 2090
High power BI-Phase Current Simulator to generate external trigger. (ASI 701B)
In my program i need to do different things in the same time:
1)i need to reshape signal from simulator (I use lv_retirg-pulse-gen0.vi for do it ). Signal from ASI 701B is connected with pin PFI0 (input). And counter is setted on pin Counter0.
2)Read spikes from simulator and acquire data (channel's spike (ai0 is connected with output Counter 0))
3) Acquire images with my camera. Camera is connected to pin counter 1 and it need to start when spikes are generated.
I found different problem:
a)I have error 50103 on Daqmx StartTask.vi in camera line
b) if i try to resolve problem with error 50103: -camera doesn't start but i have reshape and i can read spike
- or camera starts but i cannot have reshape and i cant' read spike
- or camera starts when reshape and reading spike stopped (this option it's not considerable because i need to do those operations in the same time)
Moreover i try to introduce in camera line daqmx_trigger to set trigger for start camera, using same source of counter0 (PFI0), so that camera starts when spike begin, but doesn't do what i need.
I hope you can understand what i'd like to do.
Thank for your attention
Mariangela
Attachments:
schema prog.jpg ‏266 KB

Ok thank you, however I think it's a conflict problem between devices, too.
I divided my program in 2 parts.
Part A: needs to reshape signal (part down with counter 0) and to acquire spike (part up with Analog Input)
(reshape needs to have a sampling rate lower than usual)
Part B: needs to set camera:start camera, allocate memory, acquire images and in the end save them (but i omitted this part).
I hope now it's clearer to read and understand
Mariangela
Attachments:
Part A.jpg ‏108 KB
part B.jpg ‏98 KB

Dividing incoming train of pulse signals into individual pulse signals

Hello,
I am acquiring the pulse signals using DAQ with sample rate of 500Hz.In the attached image the first signal corresponds to 1 second duration samples of pulse signal and second with 10 second duration collected using collector.Now I want to divide and save this incoming pulse signal as periods such that each period contains a pulse signals.The main problem is that the each incoming samples of 1 sec duration doesn't actually contain a single pulse but sometimes contains the two half's corresponding to two different pusle signals.
Can I know how to divide this incoming samples so that I can save the last four pulse signals in four periods so that they can be used to average the current pusle signal to make it better if it doesn't have the same shape or very different amplitude to the previuos one's.
Attachments:
Incoming_signal.PNG ‏181 KB

I want to divide the signal into periods such that it contains sample values(amplitude) from the satrting index of a pulse to the next index of another pulse as shown in the attached image.
Attachments:
pusle_division.PNG ‏85 KB

How to measure Pulse signals

Hello, Friends
I am interested in developing a data acquisition program from a sensor that gives a pulse signal. I would like that send me please some information about what VI’s I have to use inorder to began the acquisition and How I can measure the pulse frecuency. Some examples will be very excellent.
Please, write me. I will be very thankful
Pablo

You should be able to findout the output of the signal, is it an analog voltage or is this pulse a digital pulse (ie measuring TTL Width or some number of counts for a frequency changing pulse train)? All this is either done with DAQMX analog in vis or counter vis. You really need a clear picture of what the signal is before you can write code. The code should be simple once you know your signal.
Paul
Paul Falkenstein
Coleman Technologies Inc.
CLA, CPI, AIA-Vision
Labview 4.0- 2013, RT, Vision, FPGA

Niscope for pxi5105, use a digital pulse signal to control analog signal sample

i want to use ni-scope to drive pxi5105. And the PFI1 connect to a digital pulse signal(10KHz, 0-3.3V), to control a single channel analog signal continuous sample(Chan 0). I want a loop when the digital signal falling, the analog singal start to sample, and when the digtal signal rising, the analog singal stop. And by the low level of the digital singal, the analog singal sample (coupling by DC) can get an average and export to txt. I have tried the "start_and_reference_trigger.vi " and it did not work correctly. i need your help, thank you very much.
Attachments:
start and stop triggers for analog sample.vi ‏94 KB

Hi Phil,
The SCC carrier is only conditioning your signals (i.e. if your signals are not in optimal ranges, bandwidth or need external excitation). The actual counters and all digital lines are controlled directly by the M-series board. This means you will never be able to refer to a counter in the SCC module.
If you route the signals of the M-Series board, is as if you had done so externally from the SCC. Look at this example and might give you more insight to how to implement it (This is software timing). The hardware timing would be doing correlation DIO. Here is an example that needs to be modified to adapt to your timing: http://zone.ni.com/devzone/cda/epd/p/id/4414
Hope this helps,
Yardov
Gerardo O.
RF Systems Engineering
National Instruments
Attachments:
Finite Dig Output High.vi ‏31 KB

Acquire remote signal

Hello everyone,
Maybe somebody know how to do this, or can redirectme to a different post.
I have a cDAQ1972 connected to a computer, both, located 1/8 of a mile away and 3 floors up from my desk-computer. While walking time to time to reprogram is great for my health, it is also a pain.
Is there a way to acquire the signals remotely? (All the computer are in a network)
Thanks

Hi Roddy-
There is no way to control the CompactDAQ chassis reliably and remotely over a network. People have been known to use USB hubs, but this setup is not supported or recommended by National Instruments. That being said, here are a couple of suggestions:
1 - Have you tried Remote Desktop Connection? This won't stream raw data to your desk PC, but it will allow you to program on your test machine from your desk machine (remotely).
2 - Have you looked into getting a compactRIO? You can actually load programs on the cRIO and it can be configured to send data over a network.
I hope this information is helpful. Best of luck with your application!
Gary Parente
Applications Engineer
National Instruments
Gary P.
Applications Engineer
National Instruments
Visit ni.com/gettingstarted for step-by-step help in setting up your system.

Can't acquire continuous signal

Hi-
I am trying to acquire a continuous signal using the Daqmx acquire data
vi. I have the scan rate set for 100,000 (which is fine for one
channel) and the samples set to 10,000. The output on the graph
is the same no matter if I select "continuous" acquisition or "N
samples" in the Acquire Data.vi. The graph and chart seem to
update every few seconds as opposed to continuously. Also, I am
unable to stop running the program by pressing the "stop" button.
I have to abort the program. I've attached the program
below. If anyone has any thoughts, I would appreciate it-
Sherri
Attachments:
Datalog17122005.vi ‏450 KB

Your stop button has to be wired to something to actual stop and the normal thing is to wire it to the termination terminal of a while loop. Clicking the run continuous button on the toolbar is not the normal way to operate a VI. This should never be used except for occasional debug purposes. Put your code inside a while loop, wire the stop button and retry. There are numerous shipping examples on continuous data acquisition. Take a look at them to see what I mean. I've never really used the DAQ Assistant so I can't say whether you still won't have a discontinuity in your acquisition. If you do, using the DAQmx functions themselves instead of the assistant should solve your problems.

How can I use counters to read the difference between two external pulse signals?

I generated a pulse signal and sent it to a sensor which in turn gives me a pulse signal back. I need to read the time from which the sent the signal goes high to the time that the signal is returned. How can I read this? the diagram is attached
Attachments:
Timing_Diagram1.doc ‏256 KB

There is vi called "Two Edge Separation Mesurement (NI-TIO).vi". In LV6.1 it is in "c:\...\LabVIEW 6.1\Examples\DAQ\Counter\ni-tio.llb".
Unfortunately this function has no timeout. This means that your program will hang on if there are no pulses. I have attached an improved version of this vi with a timeout(sorry for the french text in the description). There are also some other improvements like the calculation of the edge separation in seconds (not only clock counts).
This function will only work with NI-TIO cards (like 660x).
Attachments:
Two_Edge_Separation_Measurement_with_Timeout_(NI-TIO).vi ‏103 KB

How can I use counters to read the difference between two expernal pulse signals?

I generated a pulse signal and sent it to a sensor which in turn gives me a pulse signal back. I need to read the time from which the sent the signal goes high to the time that the signal is returned. How can I read this? the diagram is attached
Attachments:
Timing_Diagram1.doc ‏256 KB

Hello;
The way to accomplish that is by using one of the 660x boards, and configure the counter to do "Edge Separation Method".
That method will increment the counter event count value every time a pulse comes into its source input. The counters only increments between the rising edge of the aux line and the rising edge of the gate. The current value of the counter is read when the counter is finished or an error occurs. You need to wire the out pulse to the AUX line, and the return pulse to the gate line of the counter.
Hope this helps.
Filipe A.
Applications Engineer
National Instruments

I need to acquire impulsive signal(s) and then write them to a file - but I need a good approach

Okay, I am pretty new to Lab View, and would appreciate suggestions of how to approach a problem.
My
only LabView experience has been writing a simple .vi to acquire
voltage signals in a loop at a certain sample rate, get 5 of them each
time the loop iterated (it did so every second), average the 5 samples,
and dump them into a file at every loop iteration.
That
was for continuous data acquisition while viewing/monitoring the data
at the same time, and was probably not the most efficient way (or even a
good way) to do it.
Now,
I am doing something different. I want to record voltage signals but
only after a trigger event has occured, and only until a certain time
window after the trigger event.
Should I use continuous data sampling?
Or should I sample "N" samples?
Should I use "producer / consumer" structure?
Should I continuously log to a TDMS file (I just started reading about that.... I used lvm files before....)?
I
am very confused. I have enough programming knowledge to be dangerous,
but am very new to Lab View. Any quick pointers to get me started?
This is sort of time-critical....
Thanks a lot
-Jay

Jay,
There are quite a few examples in the example finder of how to implement various types of triggers IIRC.
How long is your time window and how fast do you want to sample? That will probably determine whether you want to use N samples (for shorter time windows where all your samples will fit in the hardware buffer) or continuous (for when you will want to make several reads before you have enough data).
Producer/consumer is a very versatile design pattern. If you have a long running acquisition that you'd like to be able to cancel or update the UI mid run then you might want to use it. If, on the other hand you are doing a quick (in UI terms) acquistion then there may not be any need. Templates and design patterns also become more important the longer you plan to keep the code around -- the more you plan to maintain and add onto the VI the more thought should go into the design.
File format is often a personal preference. TDMS is a richer file format (faster, smaller, IMO normally better) than LVM (essentially just a text file). TDMS files can be opened in Excel with a plugin or natively in any NI tools (LabVIEW, DIAdem etc.) Text files such as LVM can be opened with just about anything. One thing that may force your decision is if you are acquiring large amounts of data quickly (too fast to buffer in RAM) then you'd definitely want to use TDMS as it is much faster and gives your hard drive a chance to keep up with the inflow of data.
Good luck, let us know how you get on.
~Simon

HT4972 Tried to acquire NBC 2012 Olympics app. App noted that I need to acquire the iOS5 to complete the free install. Did the update (sync) via my pc computer. After update (sync), still can't acquire the app noted earlier. Pls advise. Thanks

I have an iPad2. Tried to acquire NBC 2012 Olypic app. Unsuccessful for the reason that it is recommending an iOS5. I updated (sync) my iPAD2 via my pc laptop computer. Still asking for an iOS5. Please advise on what I need to do. Thanks

Are you sure that the update was successful? Go to Settings>General>About>Version. Does it show that you are running iOS 5.1.1 in there? If it does show that you have iOS 5.1.1 on the iPad, try restarting or resetting the iPad and then try to download it again.
Restart the iPad by holding down on the sleep button until the red slider appears and then slide to shut off. To power up hold the sleep button until the Apple logo appears and let go of the button.
Reset the iPad by holding down on the sleep and home buttons at the same time for about 10-15 seconds until the Apple Logo appears - ignore the red slider - let go of the buttons.

I am trying to acquire pulse signal (TTL 0 ,+5v) using parallel port (SPP 25 pins) on pin 12.

Similar Messages

Maybe you are looking for