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opto-isolator board

I'm looking for an opto-isolator board. I have some custom hardware that I'm building, that will have a digital optical output. I need an interface card that take these signals and feed them into a PC or laptop.

 

Although it appears NI does not have such a card, I'm looking for something off-the-shelve , perhaps something tha plugs into an NI chassis (like PXI perhaps?), so I can can use the standard hardware and software for further development.

 

Can anyone offer any suggestions please?

 

Thanks a lot!

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ttfan,

 

Thanks for posting on the NI Forums. If you are looking for an opto-isolated board we do have boards that have this type of isolation. The series is any of the 651X. Take a look at the PCI/PXI-6511 or any of the other boards in that line. Hope this helps. 

Aaron W.
National Instruments
CLA, CTA and CPI
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Thanks a lot for the suggestion Aaron!

 

This card may well be suitable.

 

Strangely enough I've gone through the datasheets, and it does not mention anywhere how fast the I/O is on this card... all it mentions is a propagation delay of 80us, which does seem rather slow...

 

Do you know what the speed is, or if there's a faster card?

 

Thanks a lot!

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ttfan,

 

The Digital I/O for these cards are all software timed, just meaning that there is no timing engine on the card for the DIO. How fast of rates do you need to sample with this DIO Card?

Aaron W.
National Instruments
CLA, CTA and CPI
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Probably around 20MHz...
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ttfan,

 

The only boards that we have that are going to be able to perform those rates and use the DAQmx driver are the PCIe/PXI-6536, 6537,  the PXI / PCI-6534. We also have devices that use another driver called High Speed Digital Input and Output or HSDIO. These devices are higher speed than the 20 MHz that you need, but the models are the 654X and 655X. 

 

Could you give me more details on exactly what you need to be opto-isolated, do you need each channel to be isolated from one to another? If you could also give me a good understanding of exactly what you mean by opto-isolated. You also mentioned that you have a digital optical output, where are you getting this output, is this like some sort of a laser signal, could you clarify? 

 

What signals will this digital optical output be supplying your acquisition board? Could you give me some information on voltage levels. 

 

What type of clocking source are you going to be using? Will you be supplying the device with an external clock, or as I assume you need to the clock to be internal to the acquisition device. Overall, I would just like more information about your application so I could better suggest hardware choices for you. Thanks!

Aaron W.
National Instruments
CLA, CTA and CPI
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Thanks for your help Aaron!

 

Could you give me more details on exactly what you need to be opto-isolated, do you need each channel to be isolated from one to another? If you could also give me a good understanding of exactly what you mean by opto-isolated. You also mentioned that you have a digital optical output, where are you getting this output, is this like some sort of a laser signal, could you clarify? 

 

Ok, I have a custom data aquisition module that has not been designed yet. I have good reason for needing this to be custom made, but I won't go into details. This custom module will have at least 8 channels of digital data (probably coming out of an EPLD, and can be serial or parallel), and a clock if required. This data needs to be transferred to a PC/laptop. To avoid ground loops and potential inteference, there must be NO ground connection between the custom module and PC/laptop. 

 

Hope that explains it well enough... thank you again for yuor help!
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ttfan,

 

You could always use the PCIe-6536 device in Single Ended mode and then you wouldn't connect the grounds between the two devices. I have attached a link to the PCIe-6536. Take a look through the documentation and let me know if this is something that might work for your application. Thanks!

 

PCIe-6536

Aaron W.
National Instruments
CLA, CTA and CPI
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ttfan,
If you need your board to be isolated and it hasn't been designed yet, would it be easier (and cheaper) to do the isolation on your board and communicate to a normal HSDIO card? (the 6536 looks like an excellent candidate)
There will of course be SOME current flowing between your board and the PC (it's rather hard to communicate over wires without moving an electron or two, and that current requires a return path), but isolation would keep this from touching whatever it is you're building.
Speaking of which... a data acquisition module that NI doesn't make?  Now I'm curious 😉  Product suggestion!

ttfan wrote:

I have a custom data aquisition module that has not been designed yet. I have good reason for needing this to be custom made, but I won't go into details.


 Try me 🙂
 
If you'd like to learn more about digital isolation and keeping measurement ground away from talking-to-the-PC ground, here are a couple good summaries:
http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=17390 
http://www.edn.com/contents/images/6685961.pdf
I'm a fan of Analog Device's ADUM series with isoPower (because they provide power), and TI's capacitive isolators.
 
Hugs,
memoryleak 

 

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PS:

 

I haven't had a chance to play with it (yet!), but if you are going to make an acquisition module that you want to eventually connect to labview (over PXI) you might want to look at the FlexRIO line.  You might even be able to get away sans EPLD (as the flexrio has a massive FPGA that you can get to do your bidding)

 

Hugs,

memoryleak 

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