Victor SPX crashing entire can system

We have currently managed to connect talon srx(s) and victors spx(s) via can bus but one of the victos spx(s) crashes the entire can system when connected. If we connect the problematic victor spx alone to the roborio, it doesnt even show up in the connected devices at all. The leds slowly blink red btw. Is the victor spx broken or are we doing something wrong ?

Are you sure you’ve plugged it in correctly?

Alternating Red LEDs Slowly indicates no CAN/PWM detected.


(Blink code chart is on page 11)

I controlled it many times and other working victor spxs are connected the same way

Use a DVM to measure the resistance between the yellow and green wires on the Victor causing your problem and compare with the same measurement with other working Victors and Talons. It may be a damaged (shorted) input on the bad Victor.

Between the greean and yellow cables there is open circuit

What are the ends of CAN wires like? Are you inserting the stripped ends of the yellow and green wires into the Wiedmuller connectors on the Roborio? If the wire strands are all “crinkly”, it is possible that not all the strands go into the hole of the connector and cause a short to the wire in the adjacent hole. Tholes holes are only 3mm apart, center-to-center. I have seen these stray strands short out VRM outputs (helped fix 3 of these at one event). The strip length for those connectors is 3/8" and is given in the documentation for the VRM and PCM, at least. A bit of the insulation should actually go down into the hole. There should not be any bare conductor visible once the wires are pushed in. Use a strong flashlight to examine where the wires go into the Weidmuller connectors from multiple angles to look for anything shiny to catch stray strands of wire and/or exposed conductors.

We are using ferrules to ensure no stray wires. I checked and tried one more time and still it is giving me the same result

Sounds like one of the cables inside has a cut inside, maybe the whole CAN panel or either it can be a shortage.
Check for connectivity between the two yellows and greens (seperetly).

1 Like

If you find an open circuit doing the test that @ShaharZai1 describes, pull gently on each of the 4 CAN wires where they come out of the body of the Victor. If it stretches and gets thin, that is where it is broken internally. There is no strain relief where the wires emerge from the case so if the wires get flexed a lot or get pulled hard, they tend to break there. You can also try stretching each of the 4 wires, a few inches at a time to find the break but you would have to untwist them.

While measuring can bus wires with a dmm i noticed that there is a short between gnd and the yellow wire on both sides. Does it mean that my victor spx is dead

The can cable inside the victor spx was causing a short. Using heatshrink tube to isolate the cables solved my problem

1 Like

Glad to hear it is fixed now. If the Victor works, it should be good to use. I don’t know what transceiver chip CTRE is using. I would expect that the chip has short circuit protection since it is a likely scenario that the chip would be exposed to.

Was it a solder bridge inside causing the short? If so, it would be good to notify CTRE so they can get their assembly house to be more vigilant when doing their QC.

Its not clear in your description exactly what/where the short is - or how heat-shrink tubing solves it. Can you send us a pic at support@ctr-electronics.com? I want to better understand what your seeing.

Not OP or affiliated with them, but I saw this on a Victor SPX last year. Some of our students tightened down the bolts holding the Victor just a little too much (not terribly tight) and the entire network started flashing red. We originally attributed it to a dead SPX since unplugging it restored communications on the bus but after loosening the bolt and seeing the top of the case spring back into shape, it worked normally ever since. It seems like the CAN wires internal to the device were shorting to the top of the case when moderate pressure was put on the mounting holes. I imagine they mean putting some heat shrink on the inside of the case to prevent this short (a piece of electrical tape would probably work just as well).

I couldn’t have described the problem better. I believe this is the exact cause of our problem, because some bolts were too tight.

Try using zip ties, Velcro or 3M Dual Lock. They are way faster than messing with nuts and bolts and hold the motor controllers securely enough. One year, we mounted the motor controllers on the bottom surface with Velcro and had no problems.

Until this year, we used double-sided tape for everything, most things had a small polycarbonate plate between them and the robot. This year we used bolts for everything that had holes for them (Sparks/CTRE stuff) , zipties for RIO, and double-sided tape for SparkMaxes.