HSDIO Custom Cable Issues

[SunshineDesign]

I took some old HSDIO SHC68-C68-D4 cables and cut the wires, cleaned off the board contacts of all wires, solder etc. I added 4 wires to connect to short coax for my DIO0 and DIO1 outputs or DIO2 and DIO3, which I used for SClk and SData for MIPI control. When I check the whole cables and NI adapters or even have an open HSDIO connector on the HSDIO instrument, I can light up all channels 0-15 with static set and read back whether they go high or not. With a blank connector into the HSDIO front panel correct orientation, correct depth of insertions, continuity check shows no short connections inter-channel, yet the test panel shows channels 1,2,7,8,13 and 14 are not active. I am not yet able to explain why. I saw one other post where the person had a similar scrambling, but didn't comment further in feedback in 2011. This is quite perplexing to making custom HSDIO cables for low distributed capacitance. The shortes NI has available is 1/2 meter and a box makes it over 2 ft and well over 150pF. We need to test with less than like 7-9 pf. Any ideas folks?

[red.free]

What hardware/module/terminal block are you interacting with?

If you disconnect the cable entirely, do you get the same behavior on channels 0,3,4,5,6,9,10,11,12, and 15 as you do on 1,2,7,8,13, and 14?

[SunshineDesign · Accepted solution]

I used an older HSDIO D2 type cable to start with, cut off the wires, stripped all the wires off the paddle board inside the connector housing to make the board clean with no wires or solder bridges. Wiring to the pads on the paddle board is a mistake. The paddle board is the issue. It does some strange connections. I lifted the connector board contacts off the paddle board and wired directly to the connector bypassing the paddle board. The photo shows the connector and paddle board with my initial trial wires for DIO0 and 1. DIO1 was not working and was grounding due to the paddle board. This effect on DIO1,2,7,8,13 and 14 was seen with the 6556 and 6570 models using these connectors. I stripped 2 full cables for 4 connectors and they all did this weird connections, so it is endemic to that boards design. I put the blank HSDIO connector on a CB-2162 break out board to ohm check continuity to and between lines and figured out what the problem was using it. I was able to see the cross connections and cross grounding that was going on. So the issue is resolved and custom HSDIO cable harnesses are now easy to make, just be sure to bypass the PXI-542x connector paddle board inside the HSDIO connector housing.connector housing.

[dgriffin91]

The connections on the paddle board are not a direct feed through. That is why you saw the behavior you did. This is NOT the recommended/supported way to make custom cables. For anyone trying to make a custom cable for NI-HSDIO/ NI-Digital instruments in the future please use the below link from NI.

Digital Instrument Custom Cables, Replacement Connectors, and Screws

[SunshineDesign]

For anyone that wants to make custom HSDIO cables using an old cable is the fastest way to get something made. Waiting on newly purchased connector ends can take months. Why should we have to wait, because NI doesn't want to support this? I vote no waiting and NI should support us better. This is a perfectly acceptable means of making quick solutions for rapid application development. NI doesn't seem to get this and refused to help with a solution and I went around them and helped myself.

[dgriffin91]

If you know you will be needing a custom cable. Then the recommended path is to use the above guide to purchase and create the custom cable. You should not be purchasing a brand new cable with the intent on disassembling it to make your own custom cable.

Though in the case where you already have extra cables. It does make sense from a timing perspective to want to disassemble them to make the custom cable. Thank you for providing this feedback so that we can work on improving this experience. 

[SunshineDesign]

It would be even more helpful if NI would release the pinout of the paddle board.