Patent ID: 8843219

Claim:
A control device comprising: a first module comprising: a first central processing unit having a first clock source for outputting a periodic first signal; a second central processing unit having a second clock source for outputting a periodic second signal; and a third clock source that has different clock characteristics from the first clock source and the second clock source, for outputting a periodic third signal to the first central processing unit and the second central processing unit; wherein: the first central processing unit detects whether or not a fault has occurred in the first clock source by comparing the first signal and the third signal; the second central processing unit detects whether or not a fault has occurred in the second clock source through comparing the second signal and the third signal; a second module comprising a third central processing unit, connected to the first central processing unit, having a fourth clock source for producing a periodic fourth signal, and a fourth central processing unit, connected to the second central processing unit, having a fifth clock source for outputting a periodic fifth signal; the third central processing unit detects whether or not a fault has occurred in the fourth clock source by comparing the third signal, inputted through the first central processing unit, and the fourth signal; and the fourth central processing unit detects whether or not a fault has occurred in the fifth clock source by comparing the third signal, inputted through the second central processing unit, and the fifth signal.