Introduction to the Cache Weigh System

The Cache Weigh System is a total solution that can be installed on a belted chain piler or conveyor system. The load cells of the Cache system are built to withstand the rigorous process of loading and unloading tons of material year after year. Visual feedback is always available with the Cache system’s display, and data is accessible via Wi-Fi connectivity. With the Cache Weigh System, growers can confidently know how much they have on hand as well as how much they are loading/unloading.

System Requirements

  • Tablet or handheld. Any device that can connect to Wi-Fi and has a browser. Works best with a screen size of 10 in. with resolution of 1280 x 800.
  • Conveyor. The Cache Weigh System works on belted chain conveyor belts. Conveyor belts that fit the following seven characteristics easily accommodate the Cache Weigh System.
    • Angle of the weighing belt does not exceed 24°.
    • No excessive mechanical vibration or bounce.
    • Crop flows smoothly across the belt where the weight measurements are made.
    • A straight section where the tops of three idler wheels on each side are aligned.
    • Belt must make continuous contact with idler wheels on both sides.
    • At least five sets of idler wheels on each side of the weighing belt.
    • The whole crop passes over the weighing belt.
    • At least 1/4 in. of room left on one end of the weighing belt drive shaft to install a tone wheel and speed sensor.

A conveyor belt that does not meet all of these characteristics may still support the Cache Weigh System. Please contact HarvestMaster with the specifics of your conveyor belt for additional directions or a custom solution for exceptional conveyor belts.

Crop Minimums

The Cache Weigh System provides the most accurate results when all of the following conditions are met.

  • The weighing belt is kept full. The crop should weigh at least 20 lbs per foot (10kg per 30 cm) of belt. Crops of potatoes, carrots, sugar beets, onions, horseradishes, carrots, or tomatoes have sufficient weight passing over the weighing belt to ensure accuracy.
  • The crop flows across the belt consistently. Continuous and even crop flow reduces the chance of crop roll back.
  • The weighing belt moves at a consistent speed without stopping and restarting.
  • Crop that has moved past the weighing belt is uploaded from the piler or conveyor belt.

Required Tools and Supplies

Tools Required for Installation

  • Combination wrench set (1/4”–1”)
  • SAE socket set (1/4”–1”)
  • High-quality cutting fluid
  • Cordless 1/2” drill
  • Set of standard drill bits, including a 5/8” bit (1/2” shank) and 1.25” hole saw
  • Allen key/hex wrench set, metric and Imperial
  • High-quality sealed butt connectors and crimping tool for electrical connections
  • Small butane torch for heat-shrink and butt connectors
  • Center punch
  • Hammer
  • Diagonal wire-cutting pliers
  • Welder (for miscellaneous mounting brackets and attaching the tone wheel)
  • Digital multimeter (DC and AC)
  • Four-foot level
  • Angle gauge

Other Installation Supplies

  • UV resistant zip ties (black)
  • Blue 243 Loctite or equivalent
  • Weld hub (or lock collar) for the tone wheel, appropriately sized (See Belt Speed Sensor Installation)

Helpful Tools and Materials

  • Standard set of screwdrivers (Phillips and flat)
  • Magnetic drill press (small, portable), for side holes in the conveyor
  • Ratchet straps
  • Work lights or headlamp
  • Cordless impact driver and socket set (1/2” drive)
  • 12-foot step ladder (300–400 lb capacity)
  • Small cordless angle grinder

System Diagram

System Components

  • The Central Control Unit (CCU) processes all of the information coming from the load cells and sensors. The CCU sends measurements to a webpage available to your tablet from its own Wi-Fi network.
  • The Load Cells weigh the crop as it passes over the conveyor belt. The load cells are mounted to two of the conveyor belt’s idler wheels, one on each side.
  • The Remote Interface provides a visual indication of the measurements received by the CCU. Through the tablet you can see and change settings and view previous measurements.
  • The Speed Sensor and Tone Wheel track the speed of the weighing belt.

Terminology

A weighing idler wheel is created when an idler wheel is mounted on a load cell.

The weighing belt is the section of the belt that is being weighed by the load cells.

How the Cache Weigh System Works

Tablet or handheld

The Cache Weigh System communicates with any internet-ready device, using a local wireless Wi-Fi network and browser. We recommend using a rugged tablet available from HarvestMaster.

A rugged tablet from HarvestMaster can use a solid mount or magnetic mount to easily affix to or remove from the conveyor.

Weighing Idle Wheel

With the load cells mounted, the idler wheels become weighing wheels. The crop is weighed (forty times per second) as it moves over the two weighing wheels.