Fieldbus function block shell with user selectable data ownership

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• the shell receiving a network request to access data on a fieldbus device;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned or shell owned;
• the shell accessing the data in response to determining that the ownership attribute of the data is shell owned;
• wherein, if the ownership attribute of the data is user owned, the method comprises:
• the shell invoking an access function to the user application in response to determining that the ownership attribute of the data is user owned;
• the user application providing a pointer to the data to the shell in response to the shell invoking the access function;
• and
• the shell accessing the data in response to the user application providing the pointer to the data to the shell.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• the user application providing a pointer to the data to the shell;
• creating a semaphore which controls accessing of the data, wherein the semaphore ensures mutual exclusion for accessing the data by the user application and the shell;
• receiving a request to access data on a fieldbus device after said providing and after said creating the semaphore;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned, shell owned or user pointer ownership;
• the shell accessing the data in response to determining that the ownership attribute of the data is shell owned;
• and
• the user application accessing the data in response to determining that the ownership attribute of the data is user owned.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• receiving a network request from a remote device to access data on a fieldbus device;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned or shell owned, wherein the ownership attribute of the data is user owned;
• the shell executing an access function to access the data in response to determining that the ownership attribute of the data is user owned;
• the user application providing a pointer to the data to the shell in response to the shell executing the access function;
• and
• the shell accessing the data in response to the user application providing the pointer to the data to the shell.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• the shell receiving a network request from a remote device to access data on a fieldbus device;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned or shell owned;
• and
• the shell executing an access function to access the data in response to determining that the ownership attribute of the data is user owned;
• the user application determining if the access of data is permitted in response to the shell executing the access function;
• and
• the user application returning an error code if the access of data is not permitted.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• receiving a network request from a remote device to access data on a fieldbus device;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned, shell owned, or shell notify ownership;
• the shell executing an access notify function to request permission of the user application to access the data in response to determining that the ownership attribute of the data is shell notify ownership;
• the user application determining if the access of data is permitted in response to the shell executing the access notify function;
• and
• the shell accessing the data if the user application determines that the access of data is permitted.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• the user application providing a pointer to the data to the shell;
• creating a semaphore which ensures mutual exclusion for accessing the data;
• the shell receiving a network request to access data on a fieldbus device after said providing and after said creating;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned, shell owned, or user pointer ownership, wherein said user pointer ownership allows said user application and said shell to access the data;
• the shell accessing the data in response to determining that the ownership attribute of the data is shell owned;
• the shell invoking an access function to the user application in response to determining that the ownership attribute of the data is user owned;
• wherein, if the ownership attribute of the data user pointer ownership, said semaphore is used during accesses to the data to ensure mutual exclusion for accessing the data.

A method for accessing data on a fieldbus device in a fieldbus network, wherein the fieldbus device includes a user application executing on the fieldbus device, wherein the fieldbus device further includes a shell executing on the fieldbus device, the method comprising:

• the shell receiving a network request to access data on a fieldbus device;
• determining an ownership attribute of the data, wherein possible ownership attributes include user owned, shell owned, or user pointer ownership, wherein said user pointer ownership allows said user application and said shell to access the data;
• the shell accessing the data in response to determining that the ownership attribute of the data is shell owned;
• the shell invoking an access function to the user application in response to determining that the ownership attribute of the data is user owned;
• wherein, if the ownership attribute of the data is user pointer ownership, the method comprises:
• the shell invoking an access notify function to request permission of the user application to access the data, wherein the shell invoking the access notify function is performed in response to determining that the ownership attribute of the data is user pointer ownership;
• the user application determining if the access of data is permitted in response to the shell executing the access notify function;
• and
• the shell accessing the data if the user application determines that the access of data is permitted.