From 04:00 PM CDT – 08:00 PM CDT (09:00 PM UTC – 01:00 AM UTC) Tuesday, April 16, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
Turn on suggestions
Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for
Topic Options
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page
Glitches in output on oscilloscope and timing a wave function
IDD
Member
06-14-2005 01:39 PM
Options
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report to a Moderator
I am using a BNC-2110 box with a 6024E NI-DAQ card. I am trying to develop a code that reads a continuous signal from a sample generator, outputs it on the screen and also onto an oscilloscope. The output on the screen apears fine, however, the output on the oscilloscope shows a glitch in the signal once every second. AS it stands, my sample rate is 50000/s and the number of samples per channel is 1000. My update rate is 1000. Is there something that I am doing wrong with these numbers? And do you have any ideas as to how I may eliminate these glitches? If you can assist, please help.
Also, I am trying to make a code that would generate and output a sine wave at a specific frequency for a given period of time, say 10 seconds, then this frequency should increase automatically to another number for another 10 seconds. The user should be able to specify both the beginning frequency, the increments of the frequency, as well as the time for which the wave remains at each frequency. My code already generates and outputs a continuous sine wave, however, I need to add the previously mentioned stipulations. Any help you can offer would be greatly appreciated.
Also, I am trying to make a code that would generate and output a sine wave at a specific frequency for a given period of time, say 10 seconds, then this frequency should increase automatically to another number for another 10 seconds. The user should be able to specify both the beginning frequency, the increments of the frequency, as well as the time for which the wave remains at each frequency. My code already generates and outputs a continuous sine wave, however, I need to add the previously mentioned stipulations. Any help you can offer would be greatly appreciated.
Otis
NI Employee (retired)
06-15-2005 10:37 AM
Options
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report to a Moderator
Hi IDD,
If you are using LabVIEW 7.1 then I think this will be pretty easy. It sounds like a lot of what you are attempting can be done with some of the example programs (Help > Find Examples > Hardware Input and Output > DAQmx > Analog Generation).
If you look in the above path you will find an example called Cont Gen Voltage Wfm-Int Clk-Variable Rate.vi. In this example you will find exactly what you are looking for in regards to something that will allow you to change the rate of your analog output. This example will need some modification for your purposes, but you should get a better idea of how to do what you are trying to do. You may want to also take a look at the example Cont Gen Voltage Wfm-Int Clk-Non Regeneration.vi.
You mentioned that you were getting glitches. Those could occur do to many things. My best guess from what you mentioned is that there may be something involved with the written buffer cycling back to the beginning and repeating. When it restarts then there is a 'glitch' event. I think if you look at the above examples, then you will be able to solve both problems.
Regards,
If you are using LabVIEW 7.1 then I think this will be pretty easy. It sounds like a lot of what you are attempting can be done with some of the example programs (Help > Find Examples > Hardware Input and Output > DAQmx > Analog Generation).
If you look in the above path you will find an example called Cont Gen Voltage Wfm-Int Clk-Variable Rate.vi. In this example you will find exactly what you are looking for in regards to something that will allow you to change the rate of your analog output. This example will need some modification for your purposes, but you should get a better idea of how to do what you are trying to do. You may want to also take a look at the example Cont Gen Voltage Wfm-Int Clk-Non Regeneration.vi.
You mentioned that you were getting glitches. Those could occur do to many things. My best guess from what you mentioned is that there may be something involved with the written buffer cycling back to the beginning and repeating. When it restarts then there is a 'glitch' event. I think if you look at the above examples, then you will be able to solve both problems.
Regards,
