Drawing Set Purpose

Early in the Definition Phase of a new project, the system is described in the form of a Program Document or Request for Quotation, Preliminary Equipment List, and Conceptual Diagrams. The Systems Engineer has the responsibility of translating and consolidating the relevant information from these various sources into a detailed construction drawing set.

The primary course goal is to provide a structured approach for building producing sets that reflect the professionalism SIC routinely provides its customers. Focus will be on organization, logic, and the reasoning behind SICs’ engineering and drawing quality guidelines. This allows engineers to use reason (not memorization) to deal with daily and new situations.

The usual baseline design philosophy is to communicate the system mechanics and signal flow clearly and completely in as few drawings as possible. Drawings need to include all the information required by the three general classes of drawing usage:

• 1. Design - SIC Engineering, SIC Project Management and the system’s purchaser use the drawings in order to ascertain that the system functionality satisfies the system’s intended use and SIC’s contractual commitments.
• 2. Construction - SIC Implementation uses the drawings to build the system and SIC Engineering uses the drawings to configure and test the system.
• 3. Maintenance - The purchaser's maintenance and operations staff are the long term users of the drawings. They will use the drawings to maintain and operate their new system for at least five years after the systems integrator has left to go on to other projects.

There are a variety of definitions in Webster’s dictionary for Synoptic, but here are two that define our context:

• 1. Affording a general view of the whole.
• 2. Manifesting or characterized by comprehensiveness or breadth of view.

The synoptic drawings produced give a variety of snapshots of a television system design. The entire synoptic set (also referred to as the drawing or construction set) pictorially communicates all one needs to know about the system as a whole. The snapshots begin at the widest angle as a bird’s-eye-view of the facility’s floor plan. A Conceptual Flow Diagram provides the “big picture” of the system as interconnected operational blocks. Subsequent snapshots methodically zoom into the major blocks. The system is divided and drawn as Video, Audio, and (optional) Control subsystems; each revealing specific meaningful detail needed to build and maintain each subsystem. At the end of the drawing set are the minute details for construction of multipin cable connectors and custom fabricated panels and consoles.

Attributes of Synoptics

The purpose of synoptics is communication. We want to transfer the “encoded” information on the synoptic to our end-users in the best, most efficient way possible. To that end, synoptics should:

• Be Legible
• Be Easy To Understand
• Have All Required Information "Encoded" in The Drawing
• Use Consistent Drawing and Information Encoding Logic and Patterns
• Read Like a Book - with the big picture at the beginning and the minute details in the back.

Visualize The System and Required System Drawings

After studying the initial documents, visualize the system drawing requirements and how the system fits together. One approach is to do one or more storyboard mock-ups of the drawing set to see how the system drawings can be most efficiently and logically laid out.

Each sheet of the mock-up drawing set represents one D-size drawing and is a rough thumbnail sketch indicating the sheet's future intended content. The sketch shown here may be deceptive in that (for the sake of easy reproduction) a drawing program was used to create it. Hand sketches are, in fact, the norm at this stage.

The goal is to arrange the drawings so the drawing set “reads like a book"; with the overview drawings in front and minute details in the back. Also, try to arrange drawings in a functional order to minimize page flipping when following wires leaving one page and landing on another.

There are a couple of advantages to the "mock-up" approach. One is it lets you try out a drawing order scheme and easily reshuffle drawings if the set doesn't "read like a book." Another is the 81/2 X 11 thumbnail sketches can be used by the project’s lead engineer to communicate task assignments to other project engineers. The mock drawing set approach is recommended, but is only one of many possible approaches. Many experienced engineers can visualize the required drawings and prefer to create their drawing lists using an Excel spreadsheet only.

• Drawing List - Catalogues all drawings and synoptics in the drawing set.
  
  
• Drawing Conventions Sheet - Shows and explains drawing conventions used to create the synoptics and elevations. Copies of this sheet are kept in the Drafting Department.
  
  The Drawing Conventions sheet is a work-in-progress and will (from time-to-time) require modifications and updates. The Engineering Manager is usually the only person authorized to change this drawing. Should you encounter a situation that motivates a change to the Drawing Conventions sheet, modification requests must be made directly to the Engineering Manager.

Overview Drawings

Next are the high-level “big picture” drawings. These drawings are architectural and overview in nature and, as such, are kept together near the beginning of the set.

• Overall Floor Plan - Shows the facility floor plan inclusive of all rooms.
• Room Layouts - Show (in detail) where the racks and consoles will be located in the various facility rooms. Electrical layout, lighting, cable runs, and wall penetration information may also be in this section. The number and content of these drawings varies by project. The contract Scope of Work indirectly defines which drawings are to be provided by SIC. Room layout drawings may not even be required. The overall floor plan alone may be adequate if there is space to gracefully include the required detail.
• Rack Elevations - Show specifically where each piece of rackmounted equipment will be placed within a designated rack.
• Console Elevations - Show specifically where each piece of console-mounted equipment will be placed within a designated console.
• Conceptual Flow Diagram - Shows simplified signal flow inclusive of all systems.
• Timing Diagram (optional) - Shows lump timing delays through major processing paths. This document is important for timing analog systems and for identifying lump field and frame delays in digital and hybrid analog/digital systems. Audio path timing must match video timing to maintain lip synchronization. System size and complexity will determine if this drawing is needed.