System and method for performing class checking of objects in a graphical data flow program

A computer-readable storage media for operating in a computer system, the computer system including a display screen, an input device, and a processor operably coupled to an instrument, wherein the storage media includes program instructions for performing type checking in a graphical program executing in the computer system, wherein the program instructions implement:

• displaying on the screen a VISA session icon which represents a VISA session;
• selecting a class for the VISA session in response to user input;
• displaying on the screen a VISA function node icon which represents performance of a VISA function;
• connecting the VISA session icon and the VISA function node icon in response to user input;
• performing type propagation checking to insure that the VISA function is valid for the class of the VISA session in response to said connecting;
• and
• indicating an invalid condition if the VISA function is invalid for the class of the VISA session.

A system for performing type checking in a graphical program, comprising:

• a computer system including a video screen and an input device;
• an instrument coupled to said computer system through an instrumentation interface;
• wherein the computer system includes:
• means for displaying on the screen a VISA session icon which represents a VISA session with said instrument;
• means for selecting a class for the VISA session in response to user input;
• means for displaying on the screen a VISA function node icon which represents performance of a VISA function;
• means for connecting the VISA session icon and the VISA function node icon in response to user input;
• means for performing type propagation checking to insure that the VISA function is valid for the class of the VISA session in response to said means for connecting;
• and
• means for indicating an invalid condition if the VISA function is invalid for the class of the VISA session.

A method for performing type checking in a graphical program, wherein the graphical program executes in a computer system including a video screen, wherein the graphical program is executable to control an instrument coupled to the computer system, comprising:

• displaying on the screen a VISA session icon which represents a VISA session to the instrument;
• selecting a first class for the VISA session in response to user input;
• displaying on the screen a VISA function icon which represents performance of a VISA function which is valid for said first class of said VISA session;
• displaying on the screen a wire connecting the VISA session icon and the VISA function icon;
• changing said VISA session from said first class to a second class in response to user input;
• performing type propagation checking to insure that the VISA function is valid for said second class of the VISA session;
• and
• indicating an invalid condition if the VISA function is invalid for said second class of the VISA session.

A computer-readable storage media for operating in a computer system, the computer system including a display screen, an input device, and a processor operably coupled to an instrument, wherein the storage media comprises program instructions for performing type checking in a graphical program executing in the computer system, wherein the program instructions implement:

• displaying on the screen a VISA session icon which represents a VISA session;
• selecting a first class for the VISA session in response to user input;
• displaying on the screen a VISA function icon which represents performance of a VISA function which is valid for said first class of said VISA session;
• displaying on the screen a wire connecting the VISA session icon and the VISA function icon;
• changing said VISA session from said first class to a second class in response to user input;
• performing type propagation checking to insure that the VISA function is valid for said second class of the VISA session;
• and
• indicating an invalid condition if the VISA function is invalid for said second class of the VISA session.

A system for performing type checking in a graphical program, comprising:

• a computer system including a video screen and an input device;
• an instrument coupled to said computer system;
• wherein the computer system includes:
• means for displaying on the screen a VISA session icon which represents a VISA session;
• means for selecting a first class for the VISA session in response to user input;
• means for displaying on the screen a VISA function icon which represents performance of a VISA function which is valid for said first class of said VISA session;
• means for displaying on the screen a wire connecting the VISA session icon and the VISA function icon;
• means for changing said VISA session from said first class to a second class in response to user input;
• means for performing type propagation checking to insure that the VISA function is valid for said second class of the VISA session;
• and
• means for indicating an invalid condition if the VISA function is invalid for said second class of the VISA session.

A system for creating a graphical data flow program to control an instrument, the system comprising:

• a computer system including memory and a display screen;
• at least one instrument coupled to said computer system by an instrumentation interface;
• a plurality of function nodes stored in the memory of the computer system which perform instrumentation functions, wherein each of said plurality of function nodes includes an input for receiving class information;
• a program editor which executes on said computer system for creating and displaying a graphical data flow program on the display screen of the computer system, wherein the graphical data flow program comprises a first plurality of said function nodes, wherein each of said first plurality of said function nodes receives class information on said class information input, wherein said class information is determined by the instrumentation interface of said at least one instrument;
• wherein the program editor determines if each of said first plurality of said function nodes is valid based on said class information received at said class information input.

A method for performing type checking in a graphical program, wherein the graphical program executes in a computer system including a video screen, comprising:

• displaying on the screen a session icon in the graphical program which represents a session to at least one device;
• selecting a class for the session in response to user input;
• displaying on the screen a function node icon in the graphical program which represents performance of a function to control and/or communicate with the device;
• connecting the session icon and the function node icon in response to user input;
• performing type propagation checking to insure that the function is valid for the class of the session in response to said connecting;
• and
• indicating an invalid condition if the function is invalid for the class of the session.

A computer-readable storage media for operating in a computer system, the computer system including a display screen, an input device, and a processor operably coupled to an instrument, wherein the storage media includes program instructions for performing type checking of objects in a graphical program executing in the computer system, wherein the program instructions implement:

• displaying on the screen a session icon in the graphical program which represents a session to at least one device;
• selecting a class for the session in response to user input;
• displaying on the screen a function node icon in the graphical program which represents performance of a function;
• connecting the session icon and the function node icon in response to user input;
• performing type propagation checking to insure that the function is valid for the class of the session in response to said connecting;
• and
• indicating an invalid condition if the function is invalid for the class of the session.

A method for performing class checking in a graphical program in a computer system including a video screen, comprising:

• displaying on the screen a session icon which represents a session;
• selecting a first class for the session in response to user input;
• displaying on the screen a function icon which represents performance of a function which is valid for said first class of said session;
• displaying on the screen a wire connecting the session icon and the function icon;
• changing said session from said first class to a second class in response to user input;
• performing type propagation checking to insure that the function is valid for said second class of the session;
• and
• indicating an invalid condition if the function is invalid for said second class of the session.

A system for creating a graphical data flow program, the system comprising:

• a computer system including memory and a display screen;
• at least one device coupled to said computer system through a device interface;
• wherein the device interface is of a first device interface type, wherein the first device interface type is one of a plurality of possible device interface types;
• a plurality of function nodes stored in the memory of the computer system which perform functions to control and/or communicate with said device, wherein each of said plurality of function nodes includes an input for receiving class information, wherein at least a subset of said plurality of function nodes are only valid for certain classes;
• a program editor which executes on said computer system for creating and displaying a graphical data flow program on the display screen of the computer system, wherein the graphical data flow program comprises a first one or more of said function nodes, wherein each of said first one or more of said function nodes receives class information on said class information input, wherein said class information is determined by said first device interface type;
• wherein the program editor determines if each of said first plurality of said function nodes is valid based on said class information received at said class information input.