This issue discusses the SDW DBM3AS computer controller system that was replaced in 1997 by Sierra Automatic Doors, Inc. The new system is referred to as the "DBSX-1" controller system  and is discussed in later Technical issues.  It is not discussed in this issue.

The DBM3-AS series operator is a microprocessor controlled system.    The door will complete one full opening and closing stroke in order to learn the full open and full closed position.  This information is then used to automatically calculate the braking points on the opening and closing cycles.

This  header is NOT a structural header.  It has a substantial wall thickness and is very strong, but due to the low profile, the following rules MUST be observed:

1. ALWAYS SUPPORT THE HEADER FROM ABOVE.
2. NEVER SUPPORT A TRANSOM.
3. NEVER USE HEAVY GLASS SUCH AS ¾" OR 1" SOLID GLASS, OR BULLET PROOF  GLASS.

Because the computer controller does all of the work automatically, there is very little to do except to ensure that the installation is perfect.  The following information is intended to assist you in servicing the unit should there be any difficulties.  Even though the unit represents "high tech" electronics, there are things you can do to restore a door which is having certain difficulties.

Remember that you are dealing with delicate electronics.  Treat them with care because failures due to mishandling are very easy to detect and are not covered under the warranty.

OPERATIONAL DESCRIPTION

The computer receives signals from the motor and gearbox.  This is done through a clear plastic cable which carries infared light from an "encoding disk" mounted behind the gearbox.  The computer sends light to the disk and the light is reflected back to the computer.  The computer uses this information to speed up the door, slow the door down, brake, automatic reverse etc.  It is, therefore, very important to check the disk for dirt and to make sure the fiber optics encoding cable is not "kinked" or bent.  If the computer is not receiving signals, it will not work.  The illustrations on the following pages show the controller, connections, motor/gearbox and fiber optics cable.  The transport system is belt driven using a timing belt which is important for the computer functions.  Tension on the belt, therefore must be constant and tight at all times.