Introduction

This document describes the new fast feedback system. It is used to stabilize the beams in many places (about eighteen) in the SLC. As it is database driven and uses existing instrumentation (BPMs and correctors) it is relatively easy to add new loops. The feedback processes run on the 80386 microprocessors and hence can execute fairly frequently.

You get to the new fast feedback panels by going from the INDEX to the FEEDBACK SYSTEM INDEX to the FFBK SELECT PANEL. The old fast feedback panels are still available from the FEEDBACK SYSTEM INDEX via the OLD FFBK PANEL button. Note that the new and old fast feedbacks are two completely separate systems and are not at all integrated. We intend to eventually phase out the old fast feedback software.

Release 2.0 (which includes adaptive cascade) represents about 9 person-years of work. It is essentially complete. To make this article a useful reference document, it and the touch-panel help describe version 2.0. Parts which are not done yet are so noted in parentheses. Fast feedback was brought to you by the following people: Stephanie Allison, Susan Castillo, Bob Fuller, Tony Gromme, Phyllis Grossberg, Linda Hendrickson, Tom Himel, Karey Krauter, Dave Nelson, Lee Patmore, Forest Rouse, Bob Sass, and Hamid Shoaee.

This document only gives a brief introduction to fast feedback and explains some operating procedures. Extensive documentation is available elsewhere.

1. Every button on all 9 fast feedback touch panels has online help. The main help for some of the touch panels include descriptions of methods used and definitions of some terms.
2. The System Requirements for Fast Feedback document tells what feedback is intended to do. To print a copy when logged on to the SLC VAX,

   IBMSERVE DOC$FUNC_REQ:FBCK_SYSTEM_REQ.TEX IMMCC1 /SLACNET /TEX

3. The Fast Feedback System Design document gives a top level view of how fast feedback works. To print a copy when logged on to the SLC VAX,

   IBMSERVE DOC$DESIGN:FBCK_SYSTEM_DESIGN.TEX IMMCC1 /SLACNET /TEX

4. Fast Feedback: The First Eight Loops and Fast Feedback: The Next Four Loops give a slightly out-of-date description of the first loops which were implemented. A more up-to-date (but less detailed) list is given later in this article. To print a copies when logged on to the SLC VAX,

   IBMSERVE DOC$FUNC_REQ:FBCK_FIRST_LOOPS.TEX IMMCC1 /SLACNET /TEX

   IBMSERVE DOC$FUNC_REQ:FBCK_SECOND_LOOPS.TEX IMMCC1 /SLACNET /TEX

5. Many more documents giving the detailed design have been written. Few people will be interested in these. A list of these documents can be obtained with the following command.

   IBMSERVE DOC$FEEDBACK:.CONTENTS IMMCC1 /SLACNET