Cable Analysis Requirements
Updated May 05, 2016
This article applies to:
- Terrain Forestry
- RoadEng Forestry
To complete an analysis, you need to first define topography, setup,
tower/tail hold positions and, analysis type and parameters.
- Logging Setup
- Tower/Tailhold Positions
- Analysis Type and Parameters
Given Topography, Setup, Tower/Tailhold positions and Analysis Parameters, the Cable Analysis module will calculate the cable tensions and other results for several carriage positions between the landing and the tailhold. The values that are displayed are dependent on the screen layout and options selected. The carriage positions are automatically displayed in the Profile window. Other values such as cable tensions or midspan deflection can be displayed in sub-windows. Once the windows and options have been set up to display the results of a particular type of analysis they can be saved as a layout. A particular layout can be used to perform the same analysis on different topographies and produce comparable reports.
Topography is the ground profile under the cable. This is represented in
Terrain by a feature (see Online Help for Terrain). A Terrain feature can be
created by digitizing from a topographic map, or importing a traverse or map
document from the Survey/Map module. You can also drape a feature over a terrain
model by drawing with the mouse. Several features can exist in a Terrain file,
the feature displayed the Profile/Cable Data Windows is defined in the Profile
Window Options. Most commonly the Profile Window is set up to display the
current feature; in this case, to select a profile for cable analysis, simply
click on the feature in the Plan Window with the selection cursor (see Terrain
Online Help for more information about selecting the current feature and
displaying it in the profile window).
The Logging Setup contains information defining the yarding machine, the configuration of the cables, working tensions and carriage parameters. To create a Logging Setup, you combine yarding Equipment with a Logging Configuration.
The Equipment can be defined in a dialogue box while Logging Configurations are supplied by Softree; both are stored in a system file and are available at any time once defined. Similarly once a Logging Setup is defined it can be modified in a dialogue box (independent of constituent Equipment and Logging Configuration) and can be saved for future use in the same system file.
The location of the yarder and the tailhold and/or haulback block are stored with each feature. The tower position and tailhold/haulback position(s) are defined at the same time as a setup is chosen for the current profile. These positions and the name of the setup are then stored with the feature.
The calculations performed can be selected from various options and
parameters (e.g. load) which can be adjusted. The results of the analysis are
displayed on the screen in the Profile window (graphic) and the Cable Analysis
Data window (tabular). The format and contents of the display can be controlled
by the user.
Several Analysis options and parameters can be chosen in a Calculation Options dialogue. For example, it is possible to calculate maximum load given clearance or fix the load and calculate minimum deflection. See the section describing the Cable Analysis - Calculation Parameters dialogue for more details. These options are saved with the screen/options layout file.