Accurate time between digital on/off

Hi All
I had posted this before in software board but i think this board is more appropriate. I am operating a valve which uses a digital signal (1 or 0) to switch on and off. I need to vary the time it remains open from 5 ms to 100 ms. I was using 'wait until ms' block up till now but it is not very accurate.
I am attaching the final version of the program I am currently using. The
daq card is pci 6516. We also have a PCI 6251 which as I understand can be used
for hardware timing but am not really sure how to go about it. I
would be greatful if someone could push me in the right direction.
Regards
Abhishek
Solved!
Go to Solution.
Attachments:
DOD_valve.vi ‏27 KB

You will not be able to use the CB-37F-LP with the PCI-6251. I would recommend using the SCB-68 or the TBX-68.
SCB-68
http://sine.ni.com/nips/cds/view/p/lang/en/nid/1180
TBX-68
http://sine.ni.com/nips/cds/view/p/lang/en/nid/1182
I attached another program that will output a digital high for 5ms and then a low for 100ms (like what you asked in the beginning). This is all hardware based an relies on the clock frequency and what values I am outputting. Currently the program has a clock rate of 200Hz and outputs an array of 1 digital high bit and 10 digital low bits for every clock edge. To just send one pulse out of the card you would need to just change the array that is written to the output and change the sample clock to finite samples.
Message Edited by Jordan F on 01-16-2009 05:11 PM
Regards,
Jordan F
National Instruments
Attachments:
CorrelatedDO[1].vi ‏23 KB

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Attachments:
complementary test 2.vi ‏69 KB

Hi Frank ,
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How can I measure the time between each two successive rising edges ,using Digital Input ?

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I'm trying two measure the time in seconds between each two successive rising edges on a digital input .
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Solved!
Go to Solution.
Attachments:
Counter without time.vi ‏11 KB

Woah!
Sorry Apok, but your code is becoming way too complicated/messy. I don't think that all of those shift registers or boolean conversion/operators are needed at all.
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Spoiler (Highlight to read)
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Attachments:
Time between clicks.vi ‏9 KB

Creative Zen 8GB not keeping accurate time on cl

Hello, I am wondering if anyone else is experiencing problems with thier Creative Zen's (mine is an 8GB) not keeping accurate time on the digital clock on the player? My firmware is .2.0 by the way. I have a fully charged battery and noticed yesterday that the time on my clock was way off and needed to be set once more. So I set it correctly yesterday, now 24 hours later, the time is again way off...it thinks it's :6 pm even though it's 0:20 pm as I post this message.
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Thank you for your contacting us at Creative Technical Support; we
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I have no idea what "Time between Points, and Small Loop Delay tools" is. If this is some code you downloaded, you should provide a linke to it. And, if you want to acquire analog data every 5 milliseconds from a DAQ board, that is possible with just about every DAQ board and is not related to the version of LabVIEW. You simply have to set the sample rate of the DAQ board to 200 samples/sec. If it's digital data, then there will be a problem getting consistent 5 msec data.

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Hello Joes,
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How can I increase the transition time between songs on my IPOD? I do not want a fade.

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Attachments:
capture.GIF ‏19 KB

You're not going to be able to get even close to 1 usec resolution using the built-in time functions though I don't see any of those in your attachment. The windows clock is simply not that accurate. If you need to precisely time your serial reads you might want to look at using the timed loop. You can set the period of that to 1 msec.

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Hi Emir
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Message Edited by Jaime F on 11-05-2007 12:57 PM
Jaime Hoffiz
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Product Expert
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Attachments:
Read Dig Port1.vi ‏31 KB
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Time between songs

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ScreenPulses.doc ‏49 KB

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Accurate time between digital on/off

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