Digital Sidecar not giving PWM signal to the speed controllers

The basic problem that i have is that when I deploy the code to the cRIO, the victor speed controllers (along with spike relays and pretty much anything else hooked up to the digital sidecar) keep giving me the flashing light, like they are waiting for a signal.

Some details about the digital side car is when the code is not deployed and everything is disconnected,(except for power of course) only the BAT light is on. When I plug the ribbon cable into the digital sidecar, the 5V light comes on. When I deploy the code the 5V light goes off unless the ribbon cable is at a weird angle, then the 5V light comes on and the victor speed controls work … sometimes. Sometimes they still give me a blinking light and sometimes they get a mind of their own and go at whatever speed they deem necessary.

Things i have tried

1) Try going with the default code to see if that was the problem (It wasn't)
2) Tried unwiring the power and rewiring it
3) Tired rewiring the ribbon cable to see if it was wired backwards

Is the 6V light supposed to be on, and when is it supposed to be on?
What would be the problem?
Anything else i can try before deeming the sidecar broken?

All voltage lights should be lit on the digital sidecar. Can you post a picture(s) of your electronics set-up?


you have a piece of junk ribbon cable. I wish they had not shipped them this year.

get one of these:

also make sure the DIO module is in the cRio in slot # 2.

they aren’t big images, is there a better way to show you these (edit)

We cannot view the images. When replying to a post, scroll down and click on Manage Attachments. There, you can upload the pictures so we can view them.

Next, at the top of the the message window, there is an Attachments drop down. Your attachment should be there. Just click and it will place the attachment at your current cursor point.



The 6V light should be lit on the digital side car. However, that should only impact servos, not normal PWM outputs.

There should be a Robot Signal Light (RSL) output with an LED next to it on the DSC as well. Can you tell us what it’s doing? Does it flash?

Also, on your Power Distribution board, what do you have plugged into the 5V output? The only thing that should be plugged into that port is a camera.

It looks like you have the Solenoid power and the Digital Sidecar power swapped.

The Solenoid Breakout gets 24v power.
The Digital sidecar gets 12v power.

After looking at the pictures my issue is still with the ribbon cable. There was a batch of bad cables last year and the rework instructions on just not viable. It takes a proper crimp tool to make ribbon cable and an proper cable tester to make sure it is done correctly.

You can continue to chase other theories and fiddle with the ribbon cable while you wait on a new one to arrive but I would definitely get a new cable asap.

Statistically the most likely failures on the control chain is the software followed by the ribbon cable, followed by reversed PWM cables, IMHO.

Look again. The only thing that is getting 24V is the cRIO. The Solenoid Breakout can either take 12V or 24V.

To me it looks like they have the 5V output from the PD board connected to the digital side car. That would cause an issue. Even though the LEDs are lit (minus the 6V one), they wouldn’t have enough voltage to drive the various chips on board to enable the PWM output.

I also agree with the ribbon cable posts. Those things are trouble.

Yea, the Digital Sidecar power is obviously miswired, but the resolution of my eyes and the photo aren’t up to snuff.

okay, i realized that the ribbon cable is in fact the problem

However, fixing that problem makes it so that the victor speed controllers have signal again, but the 6V light is still not on. Is it because i don’t have a servo hooked up to it? or should it be on regardless?

It should be on regardless.

You should have 12V power from the Power Distribution board hooked directly into the Digital Side Car.

From what I can tell, you have the 5V output from the PD board hooked into the Digital Side Car.

off topic, but…

You’re driving 2 CIM motors with each Victor:

That’s a non-no.

that was the problem.
Thanks! The first wiring diagram we saw told us to use the five volt.

Good catch! Very big no no. You either need to get rid of a CIM motor on each side, or add additional speed controllers. If you decide to keep both CIM motors, you can either use a Y-PWM cable, which splits the signal (I believe these are provided in the KOP), or you can use additional PWM cables and reconfigure your Drive code to use 4-motors instead of 2-motors.

If you use the Y-PWM cable, there is no need to change your code.

Also, on topic, what documentation said to use the 5V output? Can you post a link?

Can you post the wiring diagram you’re using? This year’s FIRST wiring diagram looks ok to me.