Application Rate Controller Display Unit

Function

Application rate in L/m² equals flow rate in L/min divided by the product of vehicle speed in m/min and spray width in metres. The controller performs this calculation multiple times per second and updates the display continuously. By showing both target and actual rates, the operator can immediately adjust pump speed or vehicle speed to compensate for deviations caused by grade changes, pump wear or temperature-driven viscosity variation. The job totaliser function records total volume sprayed per run, which is essential for material accounting, contract documentation and payment certification on government road projects.

Construction & quality

Housing: heavy-duty ABS or aluminium enclosure, IP65 rated, designed for cab dashboard or external spray panel mounting. Display: full-colour LCD or backlit LCD, 4.3 to 7 inches, minimum 600 cd/m² brightness for outdoor and direct-sunlight visibility. Inputs: flow meter pulse (NPN, PNP or reed), speed sensor pulse or GPS NMEA serial, manual spray width entry. Outputs: 4–20 mA or PWM pump speed control signal, alarm relay. Power: 12 VDC or 24 VDC vehicle supply, under 5 W consumption. Data logging: internal flash memory with USB or RS232 download. Operating temperature: −20 °C to +70 °C (−4 °F to +158 °F).

When to replace

• Display does not power up or shows corrupted or scrambled characters
• Rate reads zero or pegged at maximum despite valid flow and speed sensor signals
• Application rate display is erratic or noisy — loose connector on the speed or flow sensor input
• Stored job data cannot be read or downloaded — internal flash memory fault
• Touchscreen or keypad buttons become unresponsive to repeated input