Instrument Control (GPIB, Serial, VISA, IVI)

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PXI-8430 cable design for RS-232

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I'm planning to route all 16 channels from a PXI-8430/16 to a "custom comm. box" where some will be broken out level shifted and modulated for OOK (100kHz) communication and others will just be passed through to other RS-232 equipment (600 to 9600 baud).  My question concerns the connection between the PXI-8430 and the "custom comm. box".


I want to avoid using the 68-pin VHDCI to nine DB-9 octopus cables and am considering a pair of the SHC68-C68-S, 68-pin VHDCI to 68-pin VHDCI cables, either 186380-02 (2 meter) or 186380-0R5 (0.5 meter) or one of the 186381 D-Type alternates.


I haven’t looked at the design of these cables but I’m assuming they are single bundle with one overall shield?


The system I inherited had issues with crosstalk due to haphazard bundling of multiple OOK (100kHz) channels.  Are there limitations or concerns with bundeling 8 RS-232 channels in these NI cables?





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Accepted by topic author Darrow

If Crosstalk is an issue I would not recomend the SHC68-C68S.  The calbe design is just a bit different than 1 overall shield It uses 34 twisted pairs.  From looking at the Docs HERE and Here.  You'ld be twisting each line of port 1-4 with its corresponding port 5-8 signal line.  just about garunteeing crosstalk.

"Should be" isn't "Is" -Jay
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Thanks Jeff!

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