Limit switch on Falcon and also on SparkMAX


We want to use limit switches with our falcon and Neo550 motors (the latter with SparkMAX controllers).

What cables are available to connect to the data ports?

I see a breakout box for the SparkMAX (not available on Canada right now) - is there a quick alternative?

And, for the Falcon, is there a breakout box for that data port - is there a quick alternative.

We have (in the past) used code to activate limit switches, seems easier and more efficient to connect directly to motors.

The SRX Encoder Breakout Board and SRX Analog Breakout Board both include solder pads for connecting limit switches. You’ll also need 0.05"/1.27mm pin pitch (2x5) 10 pin cables to connect the breakout boards to the motor controllers. Both breakout boards are pin compatible between the SparkMax and Talon SRX/Falcon FX dataports to my knowledge, though the encoder pins on the SparkMax are not available if using a NEO/NEO 550 motor as the motor’s internal encoders use the same pins. Personally I prefer the analog breakout for limit switches, and will either crimp my own servo/pwm connectors, or chop up cheap ones to solder as the connectors to the breakouts.

The Analog Breakout, and some cables are available currently on AndyMark, but the encoder breakout is out of stock:

And both the Analog and Encoder breakouts are available directly from CTRE, though the cables seem out of stock:

IDK about availability from these vendors to ship to/from within Canada, but hopefully this helps.

I forgot I actually soldered up a couple of Analog Breakouts earlier this week, this is the result before I put heatshrink over it. BTW, if you are going to put on heatshrink to insulate the boards, make sure to mark which of the connectors is the Analog, Forward Limit, and Reverse Limit inputs first.

There appears to be only 4 connectors on the back of the Falcon…

How would this be compatible with the Sparkmax that has 10?

Ah, that is my bad. I’ve never actually worked with Talon FXs and just assumed they also used the same connector. Everything I stated above is correct to Spark Max and Talon SRX, but not the Falcon FX.

According to the documentation, the Talon FX connector is a 4-pin JST PHR cable. Where the two outer pins are the sensor pins, and the inner two are Ground pins.

CTRE sells this one:

And while this cable from AndyMark does not explicitly state compatibility with the Talon FX, it should work.

Ofc, these are also likely readily available on Amazon as well. Just make sure they are explicitly the JST-PHR type and not any other type of JST connector.

So, to clarify, the Talon SRX encoder breakout board is compatible with the SparkMAX; pinouts are the same and the 10-pin connector is the same.

Am I right when I say that a 4-pin cable to the controller on a Falcon (it has only 4 pins and these seem to be related only to limit switching. If I could get that kind of cable then I can attach the limit switches to the Falcon motor directly. Is this cable suitable (

Correct, he Talon SRX and Spark Max 10pin Data Ports are the same connector, and have roughly the same pinout (there are small technical differences, but the 2 limit switch, analog/pwm, and A/B channel quad encoder pins are the same). I have personally used the SRX Analog Breakout for Potentiometers and Limit Switches on both the Talon SRX and Spark Max.

Also correct, the 4 pins on the back of the Falcon’s Talon FX Controller are for Limit Switches, intended to be wired for a pair of NO (Normally Open) Limit Switchs (The SRX/SparkMax breakouts generally are as well). As for if those cables are compatible, I believe so. It looks like the “PHR” bit is the model name for the “Housings” of the “JST-PH” line according to this datasheet.

Thanks - they (the cable pack from Amazon) are supposed to be delivered today - heavy snow right now so not optimistic about that… :slight_smile:

Will try this Monday and get the other compatible breakout boards and cables for the SparkMax from Studica here, in Canada (the local Andymark agent).

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Alright, we’re getting there on limit switches…

We have the AM2634 breakout box and the AM 2617 data cables. I understand that one end of each limit switch would be connected to LMTR and LMTF - the other end, I assume, to ground. There are three ground pins one shown and two more on the back. Does it matter which are used? (Just checking to be on the safe side).


They’re all configured as normally open out of the box; otherwise, they wouldn’t operate without a limit switch wired up. However, all of these motor controllers can be configured to use normally closed limit switches via the software APIs or their respective hardware clients if desired.

I don’t believe so; they should all connect back to the same GND pin on the motor controller anyway.

The GNDs are all the same. When I solder up mine, I use the GND on the front for the Analog Input, and each GND on the back for one of the limit switches, but it doesn’t matter.

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