Abstract: A management system (managing field devices of a process control plan) provided according to an aspect of the present invention enables a user to view historical menus (i.e., the menus as displayed at desired prior time points). Such a feature is enabled in an embodiment by storing displayed tree structure as well as associated item values.

Abstract: A multiplexer implemented substantially in the form of software, which enables the multiplexer to be integrated with a supervisory platform into one unit is disclosed. The multiplexer may contain a database which stores a mapping of the address of the devices to the corresponding port/channels to which the devices are connected. An emulation block implemented in software examines the address in each command/response and forwards the command/response appropriately. Due to the software implementation, some of the commands may be blocked (from being forwarded). According to another aspect, data required to generate a response may be retrieved from a controller block (instead of retrieving from the device), thereby reducing the overhead on the devices.

Abstract: A multiplexer implemented substantially in the form of software, which enables the multiplexer to be integrated with a supervisory platform into one unit is disclosed. The multiplexer may contain a database which stores a mapping of the address of the devices to the corresponding port/channels to which the devices are connected. An emulation block implemented in software examines the address in each command/response and forwards the command/response appropriately. Due to the software implementation, some of the commands may be blocked (from being forwarded). According to another aspect, data required to generate a response may be retrieved from a controller block (instead of retrieving from the device), thereby reducing the overhead on the devices.