Additional signal circuits are required when it comes to expanding capacity in processing facilities with hazardous areas of food and beverage industries, like distilleries. These signal circuits depend on measured variables from the explosion-hazardous area being transferred to the control panel and, conversely, signals from the control system being transferred to actuators in the field. Hardware intervention at interface level can have an impact on plant availability. The task is always to keep this impact at the lowest possible level.
The processes of extending or migrating a plant are always especially critical since it is necessary to intervene in a functioning system, meaning that it will be completely or partially unavailable for a specific period. Unlike greenfield projects, expansion and migration projects involve numerous specific conditions for additional elements at interface level, affecting items such as the system properties of the interface modules, space requirements, or the mounting direction of the modules. Last-minute modifications to the signal type during the commissioning phase are time-consuming but, in reality, cannot always be avoided.
To account for these requirements, Honeywell asked Pepperl+Fuchs to design the HiC2441 universal barrier. The module is part of the H-system, a termination board-based solution that guarantees permanent wiring, is available for many control systems with system connectors, and enables faster commissioning. The modules can be mounted horizontally and vertically without derating. During operation, modules can be replaced without disconnecting the wiring, and a loop check is not required after replacing a module.
The isolated barriers mounted on the termination boards limit current, voltage, and power as explosion-protected modules and are galvanically isolated from the circuits. Tested solutions that have been optimized for switch cabinets are available for a number of process control systems, including those from Honeywell. The H-System also offers versions that are not linked to a specific manufacturer. These devices are available with coded slots to enable interface modules such as isolated barriers to be installed without the need for tools. In practice, input cards from different automation systems have differing signal requirements and to date have each required corresponding I/O modules.
This arrangement can make things very complicated and time-consuming when it comes to planning, engineering, implementing, and maintaining interface solutions. What’s more, there is also the risk of barriers being mixed up due to the different types of barrier being used within distributed control and automation topographies. This could occur when performing urgent overhaul work, for example. Previously, users had to make a choice when it came to I/O interface modules, opting either for standardization or for flexibility.
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