PWM signal from Accelerometer by using DIO of PIC-MIO-16E-4

I am a new beginner to use digital signal acqusition. The accelrometer send the pulse width modualated signal and I need to use DIO line instead of counter. I wonder how I can measure the pulse width, + duty, and -duty.

Hi Gino,
If you plan to use the digital inputs of the PCI-MIO-16E-4 then you will be limited to software timing since the digital inputs are asynchronous and dependent on software calls. This means your fastest rates are roughly 100-1000Hz (computer dependent). Since you also want to sample a period at least 5 to 10 times so that you can get a somewhat accurate representation of the duty cycle and the pulse width, you are further limited to the signal being slower than 10-200Hz.
However, if this is acceptable then you only need to create a loop and sample your digital inputs at the desired loop speed and perform calculations to determine the duty cycle.
How you would determine the pulse width and duty cycle is everytime you take a digital measureme
nt you also use "Count Ticks (ms).vi" in LabView to count the time between each call to this VI. You simply add these times while the reading is high and you have the high dutycycle. Do the same for low and then add the two together.
Hope that helps.
Ron

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I am new in using labview. I need help in writing program to continuously record the signals form PXI 5105 using LabVIEW 2011. I prepared a program using help examples. It is recording the signal using pxi 5105 into the file after trigger. I tested the code using waveform generator with -100mV to 400mV, 1 kHz, sine wave. I have also attached the waveform of signal from the excel file recorded by the program. I have following queries
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Signal recording programme.vi ‏85 KB
recorded_signal.png ‏38 KB

Hi,
Sorry but I've only got LabVIEW 2010 so I can't open your file. If you can post a 2010 version I can take a look.
vinod_p wrote:
(iii) What should be the value of millisecond multiple ( I used zero)
If you are talking about the "Wait until Next ms Multiple" function then "Wiring a value of 0 to the milliseconds multiple input forces the current thread to yield control of the CPU." (from the context help for the function - press <ctrl>+h). Is this the behaviour you want?
Normally the ms multiple function is used to synchronise loops as it waits until the next multiple (be it 10ms or 10s) before continuing the loop.
-CC
"If anyone needs me, I'll be in the Angry Dome!"

How can i read pwm signals from a rc receiver using myrio??

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This is the point in the phone conversation when the mechanic tells the customer, "Why don't you bring your car in?"
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Bill
(Mid-Level minion.)
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Signal flow chart for using DIO on 5640R

Hi,
There are a bunch of good templates to get me started with analog I/O but not for digital I/O. My project needs the host to send out a value through digital lines @10MHz. Now I have a few basic questions regarding the standard procedures to work with DIO?
1. what are the essential items in the signal flow chart on host? Open session->configuration->write->initialization->close session?
2. What are the differences of opening a session using FPGA VI Reference.vi and 5640 init Generation Session.vi? They are not interchangable.
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Hi Dan,
The basic flow of programming on the Host for digital output would be similar to:
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You could use a FIFO to pass data between the host and the FPGA or you could just pass data via controls and indicators. I have included an example project which passes data from the host to a control on the FPGA VI. If you are transferring the data as a 32-bit unsigned integer then you will need to manually format and control the way it is output from the FPGA VI. There is not a pre-made function to do that.
As for testing, you can manually probe the pins on a connector with a DMM. Here is the pinout for the AUX connector.
Regards,
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Barron
Applications Engineering
National Instruments
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ni5640R Digital Output Example.zip ‏282 KB

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Iam developing an application using NI-DAQ(AT-MIO-16E)card on vc++ environment.My requirement to extract amplitude of AM signal(1khz(4step waveform) on 70Mhz carrier).Mr Ben suggested about sampling.

My application is having a device that takes 1khz and 500Hz clock and 70Mhz carrier.And generates AM signal(1khz(4stepwaveform)on70Mhz).
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Measuring PWM Signal with NI9423 with C-RIO 9073

Attachments:
Simulator1.vi ‏114 KB

Eh..sorry. I do not know what happened, but it seems like my questions is gone in my previous post.
Let me recap, I'm new to NI Components and LabView.
I wanted to measure 8 PWM Signal generated from a controller (200Hz, Max 4A, 24Vdc).
WIth NI engineer's suggestion, I bought cRIO 9073 and NI 9423 for this purpose.
I have created a VI for this purpose. It seems to be working at first, but later on, the value read by the NI 9423 becomes unstable even though the out put signal from the controller was stable.
The value read by 9423 just goes up and down with an increasing PWM signal from my controller.
below is the setting for the 9423.
Thanks.

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<Email removed by Host>

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Attachments:
are_the_results_correct.jpg ‏200 KB

First of all, thank you for quick reply. Unfortunately I don't have the acces to the vi. until tomorrow.
And yes, I think you understood correctly: essentially this arragement measures how many edges have been counted during one iteration. This is how I figured out that this could then be used as a frequency measurement:
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3. There is 2048 edges in one round of the encoder so I get the rpm as follows: rpm = (edges - delayed edges)/204,8*60(s)
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are_the_results_correct.jpg ‏198 KB

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Hi,
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PWM signal from Accelerometer by using DIO of PIC-MIO-16E-4

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