The invention discloses an input sampling device and a method thereof; the device comprises a
system I, a
system II, one and more safe input circuits, a module I, a module II and a
clock circuit. Each safe input circuit comprises an encoding circuit; the
clock circuit is respectively connected with the
system I and the system II; under the control of synchronous signals output by the
clock circuit, the system II outputs a code sequence and a reference
clock signal to the module I, the module II and the encoding circuit; the encoding circuit inputs an external level input
signal and the output encoding
signal of the system II or a previous level of encoding circuit output
signal; the encoding circuit is connected with the module I; and the module I converts the serial connection of the encoding circuit output signal into parallel connection and outputs the same to the system I, and meanwhile a
digital signature signal is inlaid in. According to the invention, a response fault-safety strategy is adopted, mixed encoding is carried out to acquired external signals, so that the safety and the reliability of digital quantity input acquisition and communication processes, the failure
identification rate and the safety level of the system are improved, quick fault identification and
fault avoidance to dangerous failure can be carried out.