Method and system for safely collecting input signals through two-out-of-two

Abstract

The invention provides a two-out-of-two safe input signal acquisition method and system, and the method comprises the steps: a first logic unit and a second logic unit perform self-inspection before signal acquisition, then the first logic unit and the second logic unit judge whether hardware of a first acquisition circuit and a second acquisition circuit has faults or not according to the self-inspection result, if the hardware has faults, a safety report is guided to be wrong, and if the hardware has faults, the first acquisition circuit and the second acquisition circuit have faults. If no fault exists, the output unit outputs an input signal, the protection circuit I and the protection circuit II respectively receive the input signal, then the acquisition circuit I acquires the input signal from the protection circuit I, and the acquisition circuit II acquires the input signal from the protection circuit II. According to the invention, input hardware circuit faults can be detected by using a self-checking function; a two-out-of-two safety input system is used, so that the safety of a safety input circuit system is improved; the anti-interference capability can be improved by using multi-frequency pulse excitation dynamic acquisition; and hardware circuit faults can be detected in real time by using encodable pulse excitation, so that timeliness is guaranteed, and readability is improved.

Description

technical field [0001] The invention belongs to the technical field of rail transit industrial control, and in particular relates to a method and system for safely collecting input signals out of two. Background technique [0002] In the safety input system in the field of rail transit industrial control, the method of fixed-level input acquisition or 1010 fixed-frequency single dynamic pulse sequence acquisition is generally used, but these two acquisition methods have defects, and the fixed-level input acquisition method The disadvantages are: 1) When electromagnetic interference is introduced from the external environment, the fixed level signal will fluctuate, causing the input system to collect the wrong level signal; 2) When the acquisition hardware circuit fails, such as a short circuit in the signal line or If there is an open circuit, the system cannot detect and troubleshoot the fault in time. The disadvantage of adopting 1010 fixed single dynamic pulse sequence a...

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Problems solved by technology

[0002] In the safety input system in the field of rail transit industrial control, the method of fixed-level input acquisition or 1010 fixed-frequency single dynamic pulse sequence acquisition is generally used, but these two acquisition methods have defects, and the fixed-level input acquisition method The disadvantages are: 1) When electromagnetic interference is introduced from the external environment, the fixed level signal will fluctuate, causing the input system to collect the wrong level signal; 2) When the acquisition hardware circuit fails, such as a short circuit in the signal line or Open circuit, the system cannot detect and eliminate faults in time

The disadvantage of adopting 1010 fixed single dynamic pulse sequence acquisition is that 1) all acquisition channels adopt the pulse excitation sequence of the same frequency, whic

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