Unlike pulse width modulation, which changes the rate by rapidly switching nozzles on and off, the Smart C Spray 124 system uses GPS and algorithms to automatically adjust the amount of chemical dispensed along the length of the spray line.
For example, a progressively higher rate is used towards the tip of the outer boom when performing a turn to account for the higher speeds. It will also switch off any nozzles on the inside boom that happen to be travelling in reverse.
The system adjusts flow by automatically switching between nozzles or using a combination of all four – a process that takes a fraction of a second. It is compatible with all nozzle types, including air inclusion and twins, and operators can select which are most suitable for the water volumes, speeds and pressure ranges they would like to work at.
As well as turn compensation, auto nozzle switching works in the body of the field to ensure the most suitable size is used for the speed at a given time. This means a smaller nozzle can be selected for rough headlands or when accelerating, with a larger one, or a combination, taking over once up to speed. By employing multiple nozzles at one time, accurate spraying is theoretically possible at speeds of 20km/h or more.
The process of deciding which nozzle or combination of nozzles should be used at a given time is calculated by some ingenious software from Lykketronic.
This runs on the firm’s own 10in touch-screen terminal, but it can also feed into any ISObus spray controller, albeit with a slightly cruder set of graphics.
Calculations start by using a GPS fix – in this case from the firm’s own NavGuide receiver – to work out how tight the vehicle is turning. Based on this information and the width of the boom, some clever algorithms work out how fast each section of the boom will be travelling.
It will then select which nozzle or combination is the most appropriate for delivering the correct rate at each location. It isn’t quite clever enough to auto-detect nozzle types, but the operator just keys in which ones are fitted in each location. With the nozzle types, water volume, operation speeds and pressures entered it will also do a quick check to make sure there is sufficient overlap between nozzles to deliver a consistent rate.
Once the software has done its job, the switching signals are sent to each nozzle body via Lykketronic’s INC 2.0 modules.
One of these units can control two nozzle bodies (up to eight nozzles) typically set at 0.5m spacings. However, other less conventional setups can be used, which might require different length leads.
Although the process of switching nozzles sounds convoluted, it all takes place in just 0.2 of a second, so there is no discernible interruption to the spray pattern.
Unlike some systems with individually programmed modules, the INC 2.0 units are identical and self-assign their location as soon as they are connected. This makes installation straightforward, as they just need to be plugged together like a daisy chain. Flashing LEDs on each module show that they are working correctly and they will display any errors on the screen, along with the location of that error.
This option also allows the system to detect blockages. By adding Altek’s line clamp flow meters to each body, the modules can spot any deviation in flow compared with other nozzles of the same size.
If the fluctuation drops below a certain percentage, the driver will be alerted that there is a blocked or partially blocked nozzle at that location.
The Smart C Spray 124 system is most effective with quad nozzle bodies, but it will also work with twins, albeit with a narrower speed and pressure range.
In operation, drivers can choose to run the system in three modes. Manual allows the selection of a single nozzle for jobs such as liquid fertiliser application, Auto switches on speed-related nozzle switching in the body of the field and Turn allows it to operate while cornering.
The system is available to order now and prices for retro-fit kits start at £25,000 for a 24m twin setup and £31,000 for a quad nozzle version.