Introduction to Acu_Calc


Table of Contents

Introduction

Welcome to Acu_Calc!

Acu_Calc is a software program for RP-8 luminance calculations that uses web-browser forms for input and output. The Acu_Calc calculation uses the roadway surface and calculation grid defined in the Acu_Calc form along with the luminaire characteristics and layout, with a separate evaluation of each of the photometric data files in the specified directory. The results are compared to the criteria chosen, and the summary shows those YES/no results as well as the numeric values. The program follows the applicable calculation procedures defined in ANSI/IES RP-8-14, American National Standard Practice for Roadway Lighting and presents results for the luminance method, and results of comaprisons to the chosen RP-8 criteria.

This discussion covers the basic information about using Acu_Calc. For additional discussion about calculations and features in Acu_Calc, including examples, read more here. For technical discussion about files etc, read more here.

Acu_Calc Form

Using the Acu_Calc Form

The Acu_Calc form provides capabilities for the different parts of input for the Acu_Calc calculation. The Acu_Calc form enables creating and changing .aci files, running calculations and viewing results. An examples form is shown to the left. The form includes a title and a set of command buttons concerning the entire file, such as Open or eXit, in the top row. The remainder of the form is input for the file, luminaire, geometry and roadway specifications. The form includes radio buttons (pick one) where suitable as well as a selection box listing available photometric files (other names can also be entered). The other fields are for text entry, with numerical information required as appropriate.

The links shown in the top row lead to numerical or graphical results or help documents (like this one), while those in the rest of the Acu_Calc form show the appropriate item in the Terminology document.


Using Acu_Calc Commands

The commands in Acu_Calc are shown in the set of buttons and links across the top of the form. The choices of buttons are New, Open, Run, Save and eXit. New and Open change which file is presented and Save writes the currently displayed file contents to the indicated name. No file protection is provided in Acu_Calc, so files can/will be overwritten without notice. This applies to files that are saved and also files produced from Run commands. The Run command will first save the current file and then use it as input for running the appropriate software. Save will just save the file without running the software. The eXit command will close the form and proceed to the MDI Software Options. No check for "save changed data" is provided. The remaining commands use links to open new browser windows. The links for Values, Contour and Shaded will show output corresponding to the current file, and examples are shown below. The ? ? ? link leads to additional information such as this document.

For any command button or link, the capitalized letter can be used with Alt as a shortcut e.g. alt-X selects eXit.


Roadway Surface and Points

The Acu_Calc calculation uses the RP-8 method of luminance. Consistent with these calculations, the Acu_Calc program includes specification for the roadway surface and values used to establish the calculation grid over the roadway surface. This information is shown on the Acu_Calc form, including the units selected and the optional descriptions. The units can be Feet or Meters, and the same units are assumed for the points and the luminaire locations. The Roadway information at the bottom of the form includes the choice of R1, R2, R3 {recommended default} or R4 surface along with the number of lanes, width of each lane, number of grid points along each lane and the distance the grid extends. Together these values describe a regular horizontal grid of points consistent with RP-8-14.

The location of a point is specified using <x, y, z> coordinates in a typical arangement with +x considered "eastward", +y "northward", and +z as upward. The grid of calculation points follows the specifications in RP-8-14. The number of points along the spacing distance ('points along') may be increased above the minimum as discussed in RP-8.


Luminaire Type

In Acu_Calc, the luminaire type is defined based on one photometric file, with additional values that are specified in the form. The file must be in IES format with a copy in the IES photometry directory selected ih the Acu_Calc form. In the form there is a list of available directories for selection. To get photometric files into the appropriate directory, use the MDI Files Utility discussed here and available from the MDI Software option page (the first page after sign-in).

The additional luminaire value is LLF (light loss factor). This values can be any positive number. For light loss focators, the LLF calculator is available through the LLF link. The same LLF value will be applied to each photometri file.


Locating Luminaires

Luminaires are located in space using conventional <x,y,z> coordinates and units specified on the Acu_Calc form, in a pattern set by the roadway geometry specifications.

In Acu_Calc, the input file specifies only one type of luminaire. Aiming for each individual luminaire is automatically set following the pattern specified (e.g. staggered). Luminaires will be oriented perpendicular to the roadway, and no other aiming is applied.


Running Acu_Calc Calculations

In the Acu_Calc form the Run button in the top row will save the current version of the input file and then run the calculation with that file for input. The software will in turn apply each of the photometric files in the selected directory in the same roadway calculation.

When the calculations are completed, the results links turn red. These links each open a separate browser window to display the chosen output. Values shows a composite text file combining several separate files (which are separately listed in the Files Utility, discussed below). The browser's Save command can be used to save a copy of the composite file.


Additional Elements

There are several additonal software elements available. One is the LLF calculator available through the LLF link. Another is the Files Utility for handling files in the MDI Software system.

The MDI Files Utility can be accessed from the page offering MDI Software options, shown immediately after signing in to the MDI Software system or by using the eXit command in any Acu_Calc form. This utility can be used to upload, view and manage files in the MDI Software system. It also provides access to the MDI Library of photometric files.

The MDI Software system includes forms for viewing account information, also available through the MDI Software options page. If the Acu_Calc program becomes unavailable, check the account status there.

This brief discussion about Acu_Calc is intended to provide an introduction without too much detail. More information is available here.


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