Shadow function block interface for use in a process control network

A controller adapted to be communicatively coupled to a plurality of field devices wherein one of the field devices includes an external function block that communicates using a device communication protocol, the controller comprising:

• a processor;
• a memory;
• and
• a control routine including a plurality of function blocks stored in the memory and implemented by the processor in a scheduled manner to control the plurality of field devices, the plurality of function blocks including;
• a multiplicity of interconnected internal function blocks configured using a controller protocol;
• and
• a shadow function block that communicates with at least one of the multiplicity of interconnected internal function blocks using the controller protocol and that communicates with the external function block within the one of the field devices using the device communication protocol, wherein the shadow function block mirrors data pertaining to the external function block received from the external function block to one of the multiplicity of interconnected internal function blocks, thereby allowing the external function block to operate as if implemented by the processor.

A method of implementing a control routine within a process controller communicatively coupled to a field device, wherein the field device has an external function block located therein and communicates using a device communication protocol, the method comprising the steps of:

• storing a plurality of interconnected internal function blocks in the controller configured according to a controller protocol for implementation in a scheduled manner as part of the control routine;
• creating a shadow function block within the controller configured according to the controller protocol, wherein the shadow function block is configured to mirror data between the external function block and the plurality of interconnected internal function blocks;
• creating a control routine that uses the plurality of interconnected internal function blocks and data mirrored through the shadow function block from the external function block to control the process as if the external function block was within the controller;
• and
• storing data associated with the external function block in the interface function block during implementation of the control routine.

A process routine implemented by a processor, the process routine comprising:

• a plurality of interconnected internal function blocks operating within the processor and, communicating according to a first protocol, the plurality of internal function blocks implemented in a scheduled manner;
• a shadow function block operating within the processor and communicating with at least one of the plurality of internal function blocks according to the first protocol;
• and
• an external device communicating with the processor via a communications network using a second protocol, the external device further including:
• an external function block operating within the external device and communicatively coupled to the shadow function block using the second protocol;
• a data transfer between the shadow function block and the external function block, the data transfer operating to mirror at least one input or at least output of the shadow function block to a corresponding input or output of the external function block, or vice versa.