NESC1033 LSAP, DIGLIB.

1. NAME OR DESIGNATION OF PROGRAM:  LSAP, DIGLIB.

3. DESCRIPTION OF PROGRAM OR FUNCTION

LSAP (Linear Systems Analysis Program) is an interactive program with graphics capability provided through DIGLIB (Device Independent Graphics Library) that can be used for the analysis and design of linear control systems. Nearly all the classical design tools are available, including manipulation of transfer functions and generation of root locus, time response, and frequency response plots. The program is capable of working with continuous time systems and sampled data systems. For continuous time systems, the Laplace transform is used and for sampled data systems, the Z-transform is used. The capability to convert from a Laplace to a Z-transform is provided. The program is intended primarily for the analysis of feedback control systems. The system configuration or parameters can be changed easily, allowing the user to design compensation networks and perform sensitivity analyses in  a very convenient manner.
DIGLIB is a collection of general graphics subroutines. It was designed to be small, reasonably fast, device-independent, and compatible with RT-11, RSX-11M, and VMS and readily usable by casual programmers for two-dimensional plotting. DIGLIB has device drivers  for Tektronix 4010, 4012, 4014, 4025, and 4027 terminals; VT100 terminals with the retrographics option; GIGI terminals, CalComp 1012 plotters, and Lexidata 3400 color graphics systems.

4. METHOD OF SOLUTION

LSAP performs its modeling by defining and operating upon polynomial fraction representations of transfer functions. It is a command oriented program. A command is entered, together with any necessary data, and then executed. The program is  then ready for the next command. The MAIN procedure accepts a command and calls the appropriate command procedure, until the program is halted. Each command procedure uses any utilities required for the execution of the command. The commands interact with global data in two basic ways. All defined transfer functions are global records, which exist in a linked list. All commands except HALT and HELP operate upon these records. Also included in global data are switches, flags, pointers, and scalars which describe the state of the program and control the operations performed by the commands.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The program can only be applied to systems which can be describeb by a collection of rational transfer functions that are either Laplace or Z-transforms. The order of the numerator or denominator polynomials cannot exceed  20.

6. TYPICAL RUNNING TIME

This varies according to the nature of the systems, the number of generated plots, the speed at which the user  can specify input data, and other factors.

NEA-DB executed the test cases included in this package on a VAX-11/780. CPU times required were 2.5 minutes for building the DIGLIB library and 7.4 minutes for compiling and linking LSAP.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS

LSAP is based on an IBM PL/I program developed by D.J. Duven at Iowa State University.

10. REFERENCES

- H.R. Brand and R.K. Yamauchi,
  PLTLIB, Graphics Library for Tektronix 4025 and 4027 Terminals,
  UCID-18981, January 25, 1981.

- A. Strecok:
  LSAP, DIGLIB Tape Description and Programmer Information.
  NESC Note 83-83  (August 22, 1983)
- T.P. Weis:
  Linear System Analysis Program - Programmer's Manual
  UCID-30183  (February 15, 1981)
- C.G. Herget and T.P. Weis:
  Linear System Analysis Program - User's Manual
  UCID-30184  (October 15, 1980)

11. MACHINE REQUIREMENTS:  One of the graphics terminals listed in item  3.

100K bytes of main storage on VAX-11/780.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  RSX-11M (PDP11, LSI11), VMS 3.2 (VAX11).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

LSAP was developed using the PASCAL 1.0 compiler. NESC attempted to test  the program using PASCAL 2.0 and was unable to obtain a usable LSAP  executable module. However, LSAP was executed successfully by NESC using the executable modules supplied by the authors. PASCAL 1.0 is  required for this release of the program.

15. NAME AND ESTABLISHMENT OF AUTHORS

   LSAP      C.J. Herget

   DIGLIB    H.R. Brand
             Lawrence Livermore National Laboratory
             P.O. Box 808
             Livermore, California 94550

File name	File description	Records
NESC1033_01.001	information file	160
NESC1033_01.002	DIGLIB source program (FORTRAN)	4146
NESC1033_01.003	LSAP modules (PASCAL)	11672
NESC1033_01.004	LSAP modules (FORTRAN)	503
NESC1033_01.005	CHECKFILE macro routine	33
NESC1033_01.006	program to split source files (FORTRAN)	19
NESC1033_01.007	module structure of file 2	70
NESC1033_01.008	module structure of file 3	42
NESC1033_01.009	module structure of file 4	4
NESC1033_01.010	command procedure to build DIGLIB	106
NESC1033_01.011	command procedure to obtain LSAP load module	70
NESC1033_01.012	DIGLIB user's manual	1681
NESC1033_01.013	guide to writing new graphics drivers	460