db25 ribbon extender

We would like to find short (6 inches or so) db25 ribbon extenders
so that we can move the breakout boards for the solenoid and
analog inputs down into spare space in the cRIO where they would
be out of harms way. We have found such on the Digikey web site,
but they do not have stock on any of them. Has anyone found these
anywhere? We would like to avoid making them.


Don’t be afraid of making them. Putting insulation-displacement connectors (“IDCs”) on ribbon cable is fun. :slight_smile:

AS Alan has pointed out, it is easy to make the appropriate jumpers. Digikey also sells both ribbon cable and the connectors. Be sure to order the right sex and connectors with the right number of pins. The NI modules are 37 pin and you must wire all pins. (Pin 37 is an enable pin I believe.) You can purchase the crimp tool to assemble the connectors or you can use a small vise. Please be sure that everything is insulated when you move the interface boards. And while we are on the subject, the jumper to monitor battery voltage at the OI must be in place on the first analog module. This is required by robot rules per R64.

<R64> A National Instruments 9201 module must be installed in slot 1 of the cRIO Mobile Device Controller. An analog breakout must be connected to this module. A jumper must be installed on the “Battery Voltage” and “Power” pins on the analog breakout.

Just for clarification I’d post the question on the official FIRST GDC FRC forum and ask if it is okay to replace the cables with ribbon cables.

For years we used ribbon cables from the IFI radio to the RCs. There is nothing technically wrong with that since it is 422, but some inspectors were uncomfortable with that and eventually last year the question was asked of the GDC and they ruled it must be the cables shipped in the KOP.

I didn’t agree with their ruling but it is what it is and that was the rule.

So to make your life more comfortable in inspection, I’d ask the question of the GDC, and if positive, your students can take a printout with them to inspection.

This question was answered in the Q&A last week and is allowed this year. Check “Ribbon cable for Digital I/O module” under the control system sub forum in the robot forum of the Q&A.

For more clarity, the Digital Sidecar uses a 37-pin cable but the Analog and Solenoid Breakouts use 25-pin cables. If memory serves, that same Q&A response also allows moving the Breakouts via ribbon cables.

Be careful if you want to move the Solenoid Breakout with a 25-pin cable - the NI 9472 is capable of driving 750mA per output but an attached ribbon cable may not be so capable.


which ribbon cables do you suggest replacing the gray cables that connect the cRIO to the digital side car with? a supplier and part number would be wonderful.

For cable, see page 46 of the online Digikey catalog
searching for MB37R-5-ND will get you there

For plugs and receptacles you can search under
HMM37H-ND for the plug
HFM37H-ND for the receptacle
and land on page 48

There are 25 pin cables, plugs and receptacles as well.

There is some shielded cable on the bottom right hand
side of page 46 as well.

As noted earlier, the current limit for the 28 gauge wire
used in this ribbon cable is listed at .228 amps and the
solenoid outputs can exceed this.

There are always the screw machine db-xx connectors
that one can resort to. We get ours from www.steinair.com.
These can handle up to 20 gauge wire and will be very reliable,
but it will be tedious to be crimping and inserting them one by one.

We’ve been doing a bit of searching for this also, thank you!