shc68-c68-D4 Cable

[instig8er]

Hi All,

         Ok I have two PCB boards one with a straight VHDCI connector and the other one with a RA VHDCI connector, between

them I want to connect a Ni SHC68-C68-D4 cable between them. Now my question is does the cable have a straight 1:1 connection

ie. Pin1 (straight) to Pin34 (Right Angle), Pin 35 (S) to Pin68 (RA), Pin2 (S) to Pin33 (RA) etc. or does the cable translate Pin1

(straight) to Pin1 (Right Angle)?

Thx Mark......

[Supreeth.K]

Hi,

This cable is meant specifically for NI R series and HSDIO cards and is not a general purpose connector. When connected to a NI 654X for eample, each pin has specific data . You can refer to this document for more information:

http://www.ni.com/white-paper/3530/en/

The gnd pins (pin4, pin6, pin 10 etc) are all connected internally which means that these pins do not have a strainght through connection between the two end connectors of the cable. Also there may be some twisted cable pairs in the cable. Therefore it is not reccomended to use this cabel as a general purpouse straight - through 68 pin cable.

Thanks and Regards,

[instig8er]

Hi Supreeth,

                    You might have prevented me from making a fatal mistake with regards to my PCB design, thank you so much. Now with the VHDCI connectors I have does NI produce a cable that is a general

purpose straight through 68pin cable, I'm guessing that will be a no but worth asking.

Thx Mark..... 

[Kyle_A.]

I wanted to comment since I answered your previous thread here differently. I want to be perfectly clear how this cable is designed so you understand the answers given to you already and the warnings provided here.

The cable has 68 pins on the VHDCI connector that are internally connected to a paddle board, which is a small PCB interface inside of your shell that covers each end of the cable. On this paddle board, the 68 pins that you see are fanned out to 80 pins in total before being routed down the cable. The reason for this is because this is an HSDIO cable, and per noise requirements, we break out a shield for every data pin so that it is protected.

The best example I can give is pin 4 on this cable. Pin 4 on one end of the cable is tied to pin 4 on the other end. However, on the paddle board pin 4 is split to pad 4 and pad 6, and routed through the cable as two lines. Then on the other end of the cable, pad 4 and pad 6 are recombined to pin 4. This pin is not meant to carry a signal, but instead intended to be GND or shield for two other data signals travelling down the cable. Therefore, if you are not following HSDIO pinout considerations with this cable, you could see undesirable results.

I'm not sure what your full application is intending to interface, or why an HSDIO cable was chosen, but I would highly recommend using a cable that corresponds to the NI hardware you are using. If you are not using NI hardware, then selecting a cable that doesn't use techniques that are particular to it's intended use will not be likely.

Are you using NI hardware on either end of this design?