Assessment: Thoughts on ExactApply Auto Select (PWM Version)

The classic (non-PWM) Auto Select on ExactApply works like a conventional three-tiered system (3TS): it switches between A only, B only, or A+B based on pressure/flow changes as speed varies—essentially the same as any pressure-regulated automatic nozzle switching setup.

In non-PWM mode, for our typical broadacre rates of 80–100 L/ha, I see no real advantage over a well-optimised fixed pulsing setup (A only, B only, or A+B manual). Duty Cycle (DC) alone handles speed variations efficiently, keeping droplet size and pattern consistent at constant pressure. When rates or spray qualities need changing, a quick console switch does the job—no need for auto-switching.

John Deere's more recent PWM-enabled Auto Select Pulsing is a step forward: it allows automatic nozzle switching (A, B, A+B) while pulsing stays active (constant pressure), and the algorithm factors in Duty Cycle alongside speed/flow demand to optimise performance.

What advantages does this offer in practice? The starting point for any 3TS/AutoSelect nozzle selection is the same: choose a pair that comfortably delivers your maximum rate at maximum speed without excessive DC.

Example: For 100 L/ha at 25 km/h on ExactApply, you'd need an effective 06 equivalent in A+B (e.g., ~3.5 bar at 80% DC). That often means an 02 + 04 combo as your only realistic pairing for Auto Select (to enable both on at peak demand).

• The 02 alone is practically useless at your rates—it's too small and would rarely engage.
• The 04 alone maxes out around 60 L/ha (3 bar, ~78% DC) or pushes to ~70 L/ha at 91% DC—still short for your common 80–90 L/ha work.

Result: For the majority of applications (80–90 L/ha), the system ends up frequently re-engaging the 02 (the smaller nozzle) to meet demand. That forces the nozzle pair into a suboptimal lower Duty Cycle.

Given that high-rate work dominates most broadacre jobs, Auto Select Pulsing isn't as efficient as sizing a dedicated fixed combo (e.g., matched 04s or 03s in A+B for V30 Hz pulsing) or a single larger nozzle. You get cleaner, more consistent operation with fewer unnecessary switches and better average DC across the board.

In summary: The PWM Auto Select is a nice evolution for highly variable-rate jobs, Multi-Rate sections, or extreme speed swings—but for consistent 80–100 L/ha broadacre spraying, a manual pulsing setup with optimised fixed nozzles usually wins on simplicity, reliability, and real-world performance.