Interface Control

Interface Control Documents Database | Interface Control Drawings Database | Interface Control Change Control Status

Ensuring compatibility among subsystems being designed and fabricated at locations throughout the world poses challenges in managing the multitude of interfaces which exist. To aid in managing this geographically diverse work, a formal interface control system has been set up. There were several steps in this process:

The subsystem breakdown generally follows subcontract or workpackage boundaries. Some of the interfaces resulting from this guideline cross Gemini group boundaries, some are contained within. Both are to be defined in the interface control documents and drawings, but the priority is placed upon intefaces which cross group boundaries. To identify the interfaces between each of these subsystems (about 100 subsystems), a graphical representation of the subsystems and interfaces was generated in the form of a modified N^2 chart. An example of a small part of this chart is shown below:

N^2 Chart
From this chart, we start with each subsystem, thinking if there exists any possible interfaces (mechanical, optical, electronic, software, etc) with each of the other listed subsystems. When in doubt, an ICD is listed (by a symbol at the 'intersection' on the chart) between the subsystems. It will be deleted later if found not needed. This method minimizes important interfaces 'falling through the cracks'.

This chart is maintained by Systems Engineering and is often referred to and updated as changes are required. To aid in the daily tracking of progress in generating the actual ICD's, an Access database tool has also been created to mimic the functionality of this chart, augmented with easy to update release information, a listing of interfaces from any particular subsystem perspective, and provision for various standard reports indicating status of interfaces in general and specic areas which are of interest to the diverse groups supporting this effort.

The actual interface documents are available electronically to those actively working on any Gemini subsystem. Contact Virginia Smith for information on accessto these documents (both in work and released documents).

These documents follow a standard format which includes references to interface drawings and other documents important to the interface being described. This reference information is also contained in the database.

As draft interface documents and drawings become available, they are circulated among the relevant parties for review. The final version is circulated by Systems Engineering for signature, archieving of the released version, distribution of the released documents and drawings, and coordination and release of changes as needed.

Each ICD contains descriptions and related drawings for each interface and is subject to formal sign-off acceptance by group managers. This results in an ICD library which serves as a repository of essential information on the overall design, operation, and integration of observatory subsystems. This organization of intefaces also serves as the basis for the Integration, Test, and Commisioning plan.

Last updated by Virginia Smith / / November 12, 2002