Yes, it is fully plug and play with the DX3S. The sensor is designed for the external data logger, he works with the same voltage.
And the signal is only a pulse. You need to extend the cable and gluing the sensor to the metal of the coil.
The hall sensor reacts to the magnetic north pole in the flywheel. You need no extra magnets (one round = one puls)
So you have a correct display of RPM.
Sorry, I have no current pics, but in this one you can see my older version, the new sensor and the point where I've glued it on the coil.
I hope it helps.