We present an apparatus for PNS threshold determination on a subject's limb, capable of narrow and broad-band magnetic excitation with pulse characteristic times down to 40 us. From measurements on 51 volunteers, we observe that PNS limits coincide for sinusoidal and triangular excitations, and are slightly lower for trapezoidal pulses. We measure significant correlations of PNS sensitivity with arm size and body weight, and none with height or gender. We confirm thresholds increase significantly for short trains also in these fast timescales. Finally, we propose our versatile low-cost system for fast offline determination of a subject's limits prior to scanning.