The PINPUT statement defines a list of VARIABLE statements that Adams Solver (FORTRAN) recognizes as system input during a LINEAR/STATEMAT analysis (see the LINEAR command).

PINPUT/id, VARIABLES=id1[,id2,...]

The PINPUT statement, along with a POUTPUT statement, is used with the LINEAR/STATEMAT command. PINPUT defines a set of inputs to the mechanical system, and POUTPUT defines the set of measured outputs from the system. The LINEAR/STATEMAT command linearizes the system equations to the following form

= Ax + Bu

y = Cx + Du

where x is the linearized system state array, u is the array of system inputs defined by the PINPUT statement, and y is the array of system outputs defined by the POUTPUT statement. This form is commonly referred to as the state space form of the system equations in control theory. Adams Solver (FORTRAN) outputs the A, B, C, and D matrices for use in a control-system design or any other linear system analysis software. If only the A matrix is required, PINPUT and POUTPUT are not necessary.

When you run an analysis type other than LINEAR/STATEMAT, the PINPUT statement acts only as a pointer to the list of the specified VARIABLE statements.

Both function expressions and user-written subroutines can access the PINPUT statement. Function expressions access the values by using the internal Adams Solver (FORTRAN) function PINVAL(i1,i2) (see the PINVAL function), where i1 specifies the PINPUT id, and i2 specifies the i2th VARIABLE in the PINPUT statement list. Note that i2 is not the id of the VARIABLE statement.

User-written subroutines call the subroutine SYSFNC to access single elements of the PINPUT list and call the subroutine SYSARY to access all values for a PINPUT (see the SYSARY and SYSFNC subroutines).

This PINPUT statement identifies VARIABLES 12, 13, and 25 as inputs to the mechanical system. These variables might appear in expressions for computing actuating forces, for instance. You may refer to this PINPUT in a LINEAR/STATEMAT command.

The PINPUT statement along with the POUTPUT, VARIABLE, ARRAY, TFSISO, LSE, and GSE statements make up the interface between Adams Solver (FORTRAN) and control design and analysis packages such as MATRIXx and MATLAB.

As shown in the figure below, PINPUT and POUTPUT act as sockets for input and output to your controller, organizing the VARIABLE wires.

The LINEAR command uses PINPUT and POUTPUT statements to identify which variables to consider system inputs and outputs when generating state matrices. A control design program can use these matrices to design a controller for the system. The resulting controller may then be included in the Adams Solver (FORTRAN) model using VARIABLE, ARRAY, TFSISO, LSE, or GSE statements. See the LINEAR command.

See other Reference data available.