Matlab is an interpretive programming language originally developed for convenient use with the LINPACK and EISPACK libraries. Matlab is appealing for accelerator physics because it is matrix-oriented, provides an active workspace for system variables, powerful graphics capabilities, built-in math libraries, and platform independence. A number of accelerator software toolboxes have been written in Matlab -- the Accelerator Toolbox (AT) for model-based machine simulations, LOCO for on-line model calibration, and Matlab Channel Access (MCA) to connect with EPICS. The function of the MATLAB 'Middle Layer' is to provide a scripting language for machine simulations and on-line control, including non-EPICS based control systems. The Middle Layer has simplified and streamlined development of high-level applications including configuration control, energy ramp, orbit correction, photon beam steering, ID compensation, beam-based alignment, tune correction and response matrix measurement. The database-driven Middle Layer software is largely machine-independent and easy to port. Six accelerators presently use the software package with more scheduled to come on line soon.

Matlab is a matrix manipulation language originally developed to be a convenient language for using the LINPACK and EISPACK libraries. What makes Matlab so appealing for accelerator physics is the combination of a matrix oriented programming language, an active workspace for system variables, powerful graphics capability, built-in math libraries, and platform independence. A number of software toolboxes for accelerators have been written in Matlab -- the Accelerator Toolbox (AT) for machine simulations, LOCO for accelerator calibration, Matlab Channel Access Toolbox (MCA) for EPICS connections, and the Middle Layer. This paper will describe the "middle layer" software toolbox that resides between the high-level control applications and the low-level accelerator control system. This software was a collaborative effort between ALS (LBNL) and SPEAR3 (SSRL) but easily ports to other machines. Five accelerators presently use this software. The high-level Middle Layer functionality includes energy ramp, configuration control (save/restore), global orbit correction, local photon beam steering, insertion device compensation, beam-based alignment, tune correction, response matrix measurement, and script-based programs for machine physics studies.