We are considering using two hall effect sensors as limit switches. We would like to connect the sensors directly to a Talon SRX. The Hall Effect sensors we are looking at (US5881LUA) require 3.5 V to 24 V and typically draw 2.5 ma ($2.00 devices Hall effect sensor [US5881LUA] : ID 158 : Adafruit Industries, Unique & fun DIY electronics and kits, data sheet: https://cdn-shop.adafruit.com/datasheets/US5881_rev007.pdf).
These sensors work fine as a DIO input on the roboRIO where the roboRIO supplies the sensor with 5V of power.
From the Talon SRX documentation, most of the diagrams I see show the limit switch connections involving two wires (basically closing a connection between ground and the limit switch input).
Forgive my ignorance here (I’m a programming mentor), but is it OK to connect these type of powered of sensors as limit switches directly on the Talon SRX?
I’d like to make the following connections:
- 5V from pin 2 on the Talon SRX to the Vdd on the sensor
- GND from pin 10 on the Talon SRX to GND on the sensor
- Vout from the sensor to pin 4 on the Talon SRX (Forward Limit)
- A 10K ohm pullup resistor across Vdd and Vout
I’m hoping it’s OK to do this. I think that’s what this statement in the User’s Guide is telling me::
Attach the Forward/Reverse Limit Switch as shown. Do not connect the GND elsewhere. The Talon
SRX provides a pull-up to 2.5v, so typically an external pull-up is not needed. Only use Talon SRX
3.3V or 5.0V power if an external pull-up is used.
If anyone could confirm that this is OK to do, or warn me that I’m about to melt my Talon, I’d appreciate it.