Mixing Talon SRX and Victor SPX on Same Gearbox

One of the teams I’m supporting this year built their drive system similar to the kit chassis, using 2 CIMs per gearbox (4 CIM drive).
Some of the electrical students want to mix Talon SRX’s with Victor SPX’s by running the motor pairs with one of each type – one to process encoder data on the SRX and to put the SPX into Follow mode.

I have not used CAN in this way and have not yet seen the new SPX’s in action, but have historically advised against using different types of speed controllers for different motors on the same gearbox. However, this advice is based on my experience with the differences in speed controller response to PWM inputs, not based on CAN control and follow modes.

Any thoughts on this? I’m not sure how “Follow” mode acts in regards to its commanded throttle curves or if these curves vary at all between the SRX and SPX enough to cause problems.

This is an advertised featured, I’d expect it to work fine. Normally the “don’t mix speed controllers” is a good idea but I think the fine people at Vex and CTRE have optimized them to make it work well.

I can second this, our programming team has been using a practice robot (basically just a drive train) with 6 mini-CIMs (3 per side) with 1 Talon SRX and 2 Victor SPX’s on each side of the drive train. We have had no issues so far with setting the Victor SPX’s to follow the Talon SRX.

The Victor SP and Talon SRX were a collaboration between CTRE and VEX, with much of the core design shared. I’ve got to assume that the Victor SPX built upon that core design and added some of the CAN function so that they will follow an SRX just as well as an SRX follows a SRX.

We’ve been running our programming base on 2 Talon SRX & 4 Victor SPX in Leader/Follower respectively for a few weeks and haven’t noticed any issues. We will be running this config on our 2018 robot as well.

My team isn’t actually running Victors with Talons, but our build captain considered it. I remember he said that he read that the percentage output between a Talon and a Victor was different enough that even in follow mode, it was a slight difference in output. We’re running 4 775Pros per side, so we are worried on amperage enough to stay clear of any issues like that.

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