DMR provides robustness to the failure of one component, and error detection in case instruments or computers that should give the same result give different results, but does not provide error correction, as which component is correct and which is malfunctioning cannot be automatically determined.
A machine with two replications of each element is termed dual modular redundant (DMR).
A machine with three replications of each element is termed triple modular redundant (TMR).
In this case, the voting circuit can output the correct result, and discard the erroneous version.
After this, the internal state of the erroneous replication is assumed to be different from that of the other two, and the voting circuit can switch to a DMR mode.