The diameter of the tree is measured with delimbing knives. The diameter sensors are connected to the delimbing knives. The length of a log is measured with the measuring wheel. The length sensor is connected to the measuring wheel.
The computer aided bucking system uses the measurement of the diameter and the measurement of the length to establish a cut zone. The estimate is based on the species of tree. The measurement of the diameter in the cutting zone must be within the limits that are programmed into the computer aided bucking system.
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| Illustration 1 | g00758406 |
Component Locations for Measuring System (1) Diameter sensor (right side). (2) Diameter sensor (left side). (3) Delimbing knives. (4) Length sensor. (5) Measuring wheel. | |
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| Illustration 2 | g00758388 |
Component Locations for Measuring System (6) Input module "I". (7) Output module "A". (8) Calculation and connection module "CU". | |
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| Illustration 3 | g00758419 |
Electrical Schematic (1) Diameter sensor (right side). (2) Diameter sensor (left side). (4) Length sensor. (6) Input module "I". (8) Calculation and connection module "CU". (9) Controller "AU". (10) Connection module "BU". | |
Diameter
The movement of two delimbing knives (3) is controlled by the delimbing knife cylinders. Diameter sensors (1) and (2) are located under the cover. The diameter sensors are connected to the delimbing knives. When only one diameter sensor is present, the diameter sensor is located on the left hand side of the harvester head.
| Quantity of Diameter Sensors for Harvester Heads | ||
| Model | Standard | Optional |
| HH45 | One | N/A |
| HH55 | One | Two |
| HH65 | Two | N/A |
| HH75 | Two | N/A |
Diameter sensor (1) is not used on the HH45. When the HH55 only has one diameter sensor, diameter sensor (1) is not used.
As the delimbing knives rotate, diameter sensors (1) and (2) send electrical signals to the computer aided bucking system. The signal will be generated for every five hundredths of a full revolution of the sensor. Each electrical signal indicates the amount of rotation of the delimbing knives from the FULLY OPEN position. When the delimbing knives are in the FULLY OPEN position the measurement of the diameter is reset in the computer aided bucking system.
The computer aided bucking system is programmed with a default setting for the position of the delimbing knives. The default setting is the total amount of pulses that are required for the delimbing knives to travel from the FULLY OPEN position to the FULLY CLOSED position. When the delimbing knives are in the FULLY OPEN position, the pulse signal is compared to the default setting. If this signal is not same as the default setting, "Diameter Error" will show on the display screen.
The diameter sensors are equipped with four wires. One wire is for the 24 VDC power supply and the other wire is for the ground. Two of these wires are for the pulse signals.
The computer aided bucking system determines the direction of rotation of the diameter sensor by the two pulse signals. One pulse signal follows the other pulse signal. The computer aided bucking system uses these two pulse signals to determine if the delimbing knives are open or closed.
Control box (8) is used to read the signals from diameter sensor (1) and (2). These two signals are averaged by control box (8). Then, one signal is sent to the computer aided bucking system by control box (8) .
Reference: Operation and Maintenance Manual, SEBU7492, "Computer Aided Bucking System for Windows® (CABSWIN)"
Length
The length measuring system measures the length of the log as the tree is processed. The length is used by the computer aided bucking system to determine the point of the log for cutting. The length measuring system is also used to record the lengths of the logs that were cut.
The measuring arm moves into the log when the feed roller arms close. The measuring arm moves away from the log when the feed roller arms open.
Length sensor (4) measures the length of the log. As measuring wheel (5) rotates, the length sensor sends an electrical signal to the computer aided bucking system. The sensor sends fifty electrical signals for every rotation of the sensor.
Each electrical signal indicates an amount of rotation of the measuring wheel from the last cut of the log. When the log is cut, the measurement of length in the computer aided bucking system is reset.
The computer aided bucking system uses the diameter and length to determine the most preferable length for the log. The diameter of the log must meet the limits that are established in settings of the computer aided bucking system.
Reference: Operation and Maintenance Manual, SEBU7492, "Computer Aided Bucking System for Windows® (CABSWIN)"