Cable logging analysis screens - click to enlarge

Cable Analysis

The Cable Analysis module provides functions for analyzing cable harvesting systems. Operating in conjunction with the Terrain and Survey/Map modules, this module simulates most common logging systems including highlead, running, standing and live skylines.

Working from either 'field run' profiles or contour maps the user can analyze payload, clearance, and line tensions. Different types of equipment and logging configuration can be rapidly evaluated. Alternately, a planner can do a quick preliminary analysis of % deflection without getting into technical details.

Deflection line profile - click to enlarge

Profile Creation 

The Cable Analysis module allows profiles to be created either from field surveys, digitized from contour maps or interpolated from digital terrain models.

Field run profiles can be keyed into the Survey/Map module or directly downloaded from a data collector. Spatial adjustments can be made to position the profiles with respect to roads, unit boundaries, tielines etc. Setting maps can be created and plotted at any scale.

Profiles can also be easily entered from topographic maps by digitizing contour intersections along the profile. UP, DOWN, SAME functions allow the planner to define elevations as points are digitized.

A third method of creating profiles uses a digital terrain model. Profile features are drawn in plan view on the screen using the mouse. The elevations are calculated automatically by 'draping' the feature over the digital terrain model.

Assign logging configuration - click to enlarge

Quick Deflection Analysis

When careful analysis of payload and line tensions is not required, the Cable Analysis module can quickly plot various carriage positions for a given midspan deflection. This is analogous to the 'third point method'.

Equipment and Logging Systems

The Cable Analysis module allows the planner to create a custom table of logging setups. Included in each setup are yarder specifications (tower height, line working tensions and weights) and cable system characteristics such as type of system (Shotgun, Highlead, Running Skyline, etc.) and carriage parameters (butt rigging, motorized carriage, grapple, etc.).

Once this table has been created, any setup can be easily selected and analyzed for a given profile.

Output sheet with several profiles - click to enlarge

Analysis and Display 

Finding a suitable yarding layout is generally an iterative process carried out by the forest engineer. During this process several different combinations of parameters are evaluated for feasibility. Using the Cable Analysis module the engineer may quickly try different scenarios such as changing the elevation of the landing, moving the tail hold, adding a tail spar or using a lighter carriage.

The Cable Analysis module provides facilities to calculate and display:

• maximum flying load for a given clearance
• deflection for fixed skyline given load
• minimum deflection given load.

 Modeling of haulback tension, clamping and non-clamping carriages is provided.

A Diagnostic Error Reporting Bar is available to assist in identifying error conditions. By simply clicking on the bar with the mouse the user is provided with a description of the error condition. A typical error condition might be 'negative mainline tension' indicating that a haulback is needed to reach this position.

Graphical and tabular results are available on the both screen and hard copy.