Understanding PWM Spraying: Advancing Precision Agriculture

Understanding PWM Spraying: Advancing Precision Agriculture

How Pulse Width Modulation (PWM) Spraying Enhances Precision and Efficiency

Pulse Width Modulation (PWM) spraying has transformed modern farming practices by enabling the precise control of droplet size, spray patterns, and flow rates without needing to adjust pressure. Systems like Capstan EVO™, Ag Leader’s RightSpot™, and ARAG’s FlowTron™ highlight how this innovative technology boosts efficiency, reduces chemical waste, and minimises drift, addressing many of the challenges associated with traditional spraying methods.

How PWM Technology Works

Pulse Width Modulation (PWM) spraying systems control the flow rate by rapidly pulsing solenoids at each nozzle rather than adjusting overall flow through pressure changes. The solenoid, installed in place of a diaphragm check valve, turns the flow on and off several times per second (measured in Hertz). This allows the system to maintain constant pressure, ensuring consistent droplet size and spray quality even as travel speeds vary.

The proportion of time the solenoid remains open during each pulse is called the duty cycle, which ranges from 0% (no flow) to 100% (continuous flow). This electronic control of the nozzle’s opening time, rather than the pressure, allows farmers to maintain steady spray patterns and consistent droplet sizes, regardless of field conditions. Additionally, the alternate pulsing of nozzles in pairs creates an even blend of droplets, ensuring uniform coverage.

GRDC PWM Sprayers Factsheet -   Click Here for download

Critical Benefits of PWM Spraying Systems

1. Enhanced Spray Precision


PWM technology allows for precise control over chemical application, ensuring the right amount of product is applied precisely where needed. This improves field efficacy, reduces chemical use, and minimises the environmental impact of over-application.

2. Reduced Chemical Drift


Drift is related to droplet size, controlled by nozzle choice and operating pressure. By maintaining constant pressure, PWM systems help produce larger droplet sizes that are less likely to drift. This is especially important when using drift-reduction nozzles, as this ensures that chemicals stay on target and do not affect nearby crops.

There are still situations where an operator may drive faster than they should simply because they avoid conventional spraying issues seen with pressure spikes. Operating at fast travel speeds remains a poor practice from a drift perspective for both PWM and traditional systems.

3. Turn Compensation


One key benefit of PWM systems like Ag-Leaders RightSpot™ and ARAG's Flowtron™ is turn compensation. When navigating curves, the inner side of the boom moves slower than the outer side, leading to over-application on the inside and under-application on the outside. PWM systems automatically adjust the flow rate for each nozzle, ensuring consistent coverage even during turns.

Reference: Nordson Precision Agriculture - illustrating turn compensation, showing how inner and outer nozzles adjust differently during a turn.

Optimising Coverage with Nozzle-by-Nozzle Control

 

One of the most significant advancements in PWM technology is nozzle-by-nozzle control. This feature ensures that each nozzle maintains a consistent pressure and droplet size, improving overall coverage across the field.

For example, Ag-Leaders RightSpot™ and ARAG's Flowtron™ excel at maintaining uniform droplet size, which is crucial for effective weed and pest control. Inconsistent droplet sizes can lead to uneven coverage, resulting in missed weeds or ineffective pest control.

 

Adapting to Changing Field Conditions

 

Traditional sprayers require constant speed adjustments to manage flow rates, leading to inconsistent spray patterns. PWM-based systems, like FlowTron and RightSpot™, separate pressure control from flow rate control, allowing operators to adjust speed without compromising spray quality. This ensures droplet size remains consistent, reducing the risk of drift at higher speeds and ensuring better coverage at lower speeds.

RightSpot-Pressure-Animation

Reference: https://www.agleader.com/wp-content/uploads/2024/07/RightSpot-Pressure-Animation.gif

Scalability and Compatibility Across Brands

 

Modern PWM systems are precise, scalable, and compatible with many sprayers, from self-propelled to pull-type models.

ARAG's Flowtron™, with its ISOBUS ECU capabilities, enables seamless integration with various multi-brand consoles, making it highly versatile for different farming operations. ISOBUS allows solutions to be compatible with popular consoles from brands like Croplands, Miller, CNH, Hardi, John Deere, and Goldacres, providing farmers with operational flexibility and a future-proof solution.

With the growing importance of data-driven farming and the increasing preference for advanced steering solutions, having an ISOBUS-capable system like Flowtron™ ensures easy integration into broader farm management practices. This compatibility allows smooth operation with farm management software such as John Deere’s Operations Centre, where data from multiple machines can be centralised, analysed, and used for precision decision-making.

Integrating an ISOBUS system enables farmers to incorporate precision spraying into a more extensive, data-centric approach to farming, offering better data control and logistical efficiency across all operations. Features like real-time nozzle control and feedback through multi-brand consoles make a highly adaptable solution that grows with a farmer’s needs.

ARAG ISOBUS FLOWTRON

Reference: https://www.aragnet.com/EN/INT/246/products/?PRD=141923

Environmental and Economic Benefits

 

Beyond enhancing precision, PWM systems offer substantial environmental and economic advantages. By reducing chemical waste and minimising drift, these systems help lower input costs while limiting the environmental impact of farming practices. Reduced chemical drift also protects nearby crops and ecosystems from unintended exposure.

 

Conclusion: Advancing Precision Agriculture

 

With the growing demand for sustainable farming and improved efficiency, PWM spraying technology is a straightforward solution for primary producers. By providing precise control over droplet size, adapting to variable speeds, and ensuring even application during turns, systems like Ag-Leaders RightSpot™ and ARAG's Flowtron™ are enabling the everyday primary producer to implement best practices for chemical application as part of their cropping programs. Their scalability and compatibility with various sprayer models make PWM solutions a future-proof investment, helping primary producers boost productivity while maintaining environmental responsibility.

 

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