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CB-2162 connector details, termination values
mlloyd
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06-22-2005 12:20 PM
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I plan to use the CB-2152 prototype board with the PCI-6551 board and have a few questions.
I was wondering if someone knows about the DIO connectors (J14 and J18) on the CB-2162 prototype board. Is the spacing on those headers 100 mil or 50 mil? Where can I find 32-pin twisted-pair ribbon cable? Does the ribbon cable impedance need to be 50 ohms? I have looked on Digi-Key and have Googled ribbon cable but to no avail...
The CB-2162 documentation does not give any insights about what the termination resistance value should be when some of the DIO channels or control signals are not being used. Any thoughts?
Thanks for whatever help you can offer. I appreciate it!
Regards,
mlloyd
I was wondering if someone knows about the DIO connectors (J14 and J18) on the CB-2162 prototype board. Is the spacing on those headers 100 mil or 50 mil? Where can I find 32-pin twisted-pair ribbon cable? Does the ribbon cable impedance need to be 50 ohms? I have looked on Digi-Key and have Googled ribbon cable but to no avail...
The CB-2162 documentation does not give any insights about what the termination resistance value should be when some of the DIO channels or control signals are not being used. Any thoughts?
Thanks for whatever help you can offer. I appreciate it!
Regards,
mlloyd
06-23-2005 10:46 AM
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I overlooked the note that refers to the NI Digital Waveform Generator/Analyzer Help. Yea for detailed information with numbers! I think I've got the termination resistor values down for generation...
The information in the help file has NO INFORMATION for acquisition on the 655x -- it only talks about the 654x and the 656x. Is ther any detailed termination acquisition information for the 655x?
Also, information on where to find a nice 32-pin ribbon cable would be appreciated!
Thanks,
mlloyd
The information in the help file has NO INFORMATION for acquisition on the 655x -- it only talks about the 654x and the 656x. Is ther any detailed termination acquisition information for the 655x?
Also, information on where to find a nice 32-pin ribbon cable would be appreciated!
Thanks,
mlloyd
AnalogKid2Digit
Trusted Enthusiast
06-23-2005 12:58 PM
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Some cable leads out of many, quick Google search on "twisted pair ribbon cable", not verified
http://www.alliedelec.com/Search/SearchResults.asp?SearchQuery=twisted+ribbon
http://www.connectworld.net/cgi-bin/iec/05MWireRibbon
http://www.selectronix.co.uk/
http://www.alliedelec.com/Search/SearchResults.asp?SearchQuery=twisted+ribbon
http://www.connectworld.net/cgi-bin/iec/05MWireRibbon
http://www.selectronix.co.uk/
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"It’s the questions that drive us.”
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"It’s the questions that drive us.”
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Alan_L
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06-24-2005 11:27 AM
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mlloyd,
Hi -- I hope all is going well.
You're in just the right place to find the information you're looking for (the HSDIO Help file). If you browse under the "Devices -> NI 655X -> Hardware Achitecture -> Channel Electronics" category, you'll find a section about "Input Impedance" among others. The Input Impedance section even include equations that can help you to calculate expected voltage levels based on the impedances of each part of your system.
As far as cabling -- probably the best off-the-shelf solution would be to get some 34-position twisted pair flat cable (http://dkc3.digikey.com/PDF/T052/0039.pdf) and mate that with a 34-position receptacle (http://dkc3.digikey.com/PDF/T052/0033.pdf, top left corner). The twisted cable has flat sections that make it easy to press on the connector. However, this is an 18" cable... so even though its pairs are twisted, that is a bit on the long side. You could probably do very well with a short 34-pin flat ribbon.
I hope that this is helpful to you!
Best Regards,
Alan L
Applications Engineer
National Instruments
Hi -- I hope all is going well.
You're in just the right place to find the information you're looking for (the HSDIO Help file). If you browse under the "Devices -> NI 655X -> Hardware Achitecture -> Channel Electronics" category, you'll find a section about "Input Impedance" among others. The Input Impedance section even include equations that can help you to calculate expected voltage levels based on the impedances of each part of your system.
As far as cabling -- probably the best off-the-shelf solution would be to get some 34-position twisted pair flat cable (http://dkc3.digikey.com/PDF/T052/0039.pdf) and mate that with a 34-position receptacle (http://dkc3.digikey.com/PDF/T052/0033.pdf, top left corner). The twisted cable has flat sections that make it easy to press on the connector. However, this is an 18" cable... so even though its pairs are twisted, that is a bit on the long side. You could probably do very well with a short 34-pin flat ribbon.
I hope that this is helpful to you!
Best Regards,
Alan L
Applications Engineer
National Instruments
06-24-2005 12:04 PM
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Alan,
You've been such a help to point me to the right cables! In looking back at the CB-2162 again I think I actually need to by 16-pin ribbon cable because it's a 2x16 header. So I could just get the 16-pin version of the cables you suggested to access all the data signals.
If there's one DIO line out of the 16 that is a no-connect on the receiver, should I terminate that signal with a 50 ohm resistor on the CB-2162? Or if I set the DIO line to high-impedance (10 kohm) can I avoid having to use a termination resistor? I would like to not have to use a termination resistor since the ribbon cable will be connected to the output pin of that signal, and I really don't want to run loose wires on the board.
Thanks so much for your help!
Regards,
mlloyd
You've been such a help to point me to the right cables! In looking back at the CB-2162 again I think I actually need to by 16-pin ribbon cable because it's a 2x16 header. So I could just get the 16-pin version of the cables you suggested to access all the data signals.
If there's one DIO line out of the 16 that is a no-connect on the receiver, should I terminate that signal with a 50 ohm resistor on the CB-2162? Or if I set the DIO line to high-impedance (10 kohm) can I avoid having to use a termination resistor? I would like to not have to use a termination resistor since the ribbon cable will be connected to the output pin of that signal, and I really don't want to run loose wires on the board.
Thanks so much for your help!
Regards,
mlloyd
Alan_L
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06-24-2005 04:40 PM
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mlloyd,
You could certainly buy a 16-pin cable... but a 34 might be a bit more handy (really a 2x17 -- there's enough room for the extra pins).
If you're using the 655x in acquisition mode you only need to connect or terminate the channels that you are actually using in software. If you're not actively reading from a particular channel, then you don't need to do anything with the unused pins.
Let me know if you have any other questions!
Thanks again,
Alan
You could certainly buy a 16-pin cable... but a 34 might be a bit more handy (really a 2x17 -- there's enough room for the extra pins).
If you're using the 655x in acquisition mode you only need to connect or terminate the channels that you are actually using in software. If you're not actively reading from a particular channel, then you don't need to do anything with the unused pins.
Let me know if you have any other questions!
Thanks again,
Alan
06-27-2005 09:35 AM
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Alan,
It's all making sense... I'm glad I don't have to worry about terminating the unused channels. It makes things a lot cleaner on the CB-2162!
I think now I have a good understanding of the details of terminating my signals and where I can find the hardware needed. It would good to put a note in the 655x documentation about not needing to terminate unused signals. Maybe it's common knowledge, but I had obviously failed to pick up on it...
Thanks again for all your help!
Regards,
mlloyd
It's all making sense... I'm glad I don't have to worry about terminating the unused channels. It makes things a lot cleaner on the CB-2162!
I think now I have a good understanding of the details of terminating my signals and where I can find the hardware needed. It would good to put a note in the 655x documentation about not needing to terminate unused signals. Maybe it's common knowledge, but I had obviously failed to pick up on it...
Thanks again for all your help!
Regards,
mlloyd
