Redundant I/O Module Reset Control Without State Switching
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Solution Overview
Problem
In safety instrumented systems, the switching of redundant I/O modules between control and standby states during resetting operations leads to unnecessary state changes, complicating failure identification and maintenance, as the cause of state switches cannot be accurately attributed to resetting operations or module failures.
Innovation Solution
A control apparatus with a storage unit for operation management information, an application executing unit for transmitting power supply signals, and a resetting unit that suspends and resumes power supply to I/O modules based on predefined instructions, ensuring that the modules remain in their pre-resetting states to prevent unnecessary state switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant I/O modules are used for resetting operations, then system reliability is improved, but unnecessary state switching occurs between control and standby modules
Solution Approach 1:
The system performs preliminary actions by storing the controlled state (running/waiting) of each I/O module before resetting operations begin. This pre-stored state information is then used after resetting to determine which module should resume control, preventing unnecessary state switching between redundant modules.
Solution Approach 2:
The system implements feedback by comparing the pre-stored controlled state with the current state after resetting operations. This feedback mechanism ensures that modules return to their original controlled states, preventing unnecessary switching and maintaining system stability.
2Ease of operation
If I/O modules switch states during resetting, then resetting functionality is achieved, but failure identification becomes difficult
Solution Approach 1:
The system performs preliminary action by recording the controlled state of each I/O module before resetting operations. This pre-recorded information serves as a reference to distinguish between intentional state changes during resetting and actual module failures, making failure identification straightforward.
3Object-generated harmful factors
If redundant I/O modules maintain pre-resetting states, then unnecessary failure notifications are reduced, but control logic complexity increases
Solution Approach 1:
The system performs preliminary action by storing the controlled state of each I/O module before resetting operations. This pre-stored information is then used to automatically determine which module should resume control after resetting, reducing unnecessary failure notifications while keeping control logic manageable through automated state restoration.
Data Source
AI summary
A control apparatus characterized by including: a storage unit that stores operation management information; an application executing unit that transmits a signal for turning off the power source of a field instrument; a resetting unit that, based on the signal, instructs to suspend the power supply from the input/output modules; and an activating unit that instructs to resume the power supply from the input/output modules, based on an elapse of preset time during which the power supply from the input/output modules should be suspended.