For the three-out-of-two signal in interlocked shutdown, is it necessary to use three different input cards? What is the actual situation?

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Hello everyone, I have a troublesome issue and would like to ask for your advice on how to deal with it. I’m not sure what others do in such situations. Our factory is a petrochemical plant. During a previous inspection by the Safety Supervision Bureau, one corrective action was recommended. Specifically, it was found that the three-out-of-two measurement signals of the interlock protection system were not connected to three separate input cards, which does not comply with the \"Design Code for Safety Instrumented Systems in Petrochemical Industries\" (GB50770-2013) and the \"Guidelines for Identifying and Addressing Potential Hazards in Chemical Enterprises\" (Safety Supervision General Administration Order No. 103 [2012]). The actual situation in our factory is that a three-out-of-two process signal is used, but the signal is connected to a single input card. After reviewing the aforementioned standards and implementation guidelines, the details are as follows: 1) In the \"Code for Design of Safety Instrumented Systems in Petrochemical Industries\" (GB50770-2013), the relevant provision is: 8.5.2 Signals from multiple transmitters that monitor the same process variable should be connected to different input cards. (Explanation of the term “yi”: it indicates that a certain degree of flexibility is allowed; one should first do this when conditions permit.) 2) In the **Guidelines for the Identification and Rectification of Hazards in Chemical Enterprises** (Safety Supervision Administration Order No. 3 [2012] 103), the relevant provisions state as follows: Under item 2.2 of the “Instrumentation Hazard Identification Form” attached to these guidelines, under the category of “Instrumentation System Configuration,” it is specified that **chemical manufacturing enterprises shall configure process control, safety instrumentation, and interlock systems in accordance with relevant standards, and shall also meet the requirements of the Code for Design of Safety Instrumented Systems in Petrochemical Industries, SH3018-2003. Process interfaces: Sensors and final actuator devices connected to input/output cards shall be designed to be fail-safe.** ； Fieldbus communication should not be used ； If a two-out-of-three process signal is used, it should be connected to three different input cards. If the implementation guidelines (high standards) are followed, corrective actions are necessary. However, carrying out such corrections is no easy task – it requires money and time, as well as downtime for the work to be done. The key issue is that our factory was built in 2005, and at that time such requirements did not seem to exist. Moreover, we use Honeywell ESD and Rosemount transmitters; Honeywell’s ESD controllers utilize three circuits for decision-making, ensuring the reliability of the output signals, which already makes them quite reliable. I wonder if there are any other solutions to report to the Safety Supervision Bureau – are there any other options, such as finding a qualified design firm or inspection company (? ) Conduct a risk assessment or use other methods, but it’s not clear whether the safety supervision agency will accept the assessment results; it’s really troublesome. First, thank you all.