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cFP-AIO-610 electrical isolation between input and output channels

Manual states "The input and output channels of the [c]FP-AIO-610 are not electrically isolated from each other". I assume this means that the commons on the input channels are connected and the commons for the output channels are connected but it does not mean that all channels on the module are connected. Is this correct? I intend to monitor two self-powered 4-20mA signals coming from a single instrument and also send two voltage signals to a different instrument. Any advice is greatly appreciated. Thanks!

 

 

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The cFP-AIO-610 appears to have channel-to-ground isolation and not channel-to-channel isolation. From the following link, I believe the AO and AI channels are not isolated between themselves. There's a little more information here:

 

http://digital.ni.com/public.nsf/allkb/CF71091043A6193B862573D70077138B?OpenDocument

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Thanks for the info. I think you are saying what I thought the module is capable of. That is inputs are tied together, outputs are tied together, but not togther, so there are effectively two commons on the module, one for input channels and one for output channels. Agreed? That's the way I read the KB article as well since this module has "bank isolation". 

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It appears that all of the channels (input and output) on the module share the same COM (see the diagram on page 4 of the manual):

 

http://www.ni.com/pdf/manuals/373174c.pdf

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Sh*t. I think you're right. I don't understand how this module is useful if you want to use both input and output at the same time. In what scenario is it likely that that having all COMs connected is going to be acceptable? Hard to imagine one...

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Why do you think there aren't situations where common AI and AO references are acceptable?  I think in most situations where it is already okay to use non-isolated channels, having common commons is just fine.

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@RavensFan wrote:

Why do you think there aren't situations where common AI and AO references are acceptable?  I think in most situations where it is already okay to use non-isolated channels, having common commons is just fine.


From the standpoint of interacting with two different instruments, such as my situation. Rarely in my experiences so far are analog communication or measurements on separate instruments going to all be referenced to the same common / earth ground. Instrument A has it's own common reference and instrument B has it's own common reference. My 20mA loop is externally powered and I can earth ground the power supply negative but the voltage output to another instrument is not but hte channels are isolated so maybe I can do it anyway. I'm hardly an expert and only trying to build my own knowledge base on how to use NI hardware. Perhaps I'm over-thinking this too much and it will work.

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