This connection example complies with the requirement of ISO/EN ISO 13849-1 category 3 PL d. 24 V EMG S4 S3 KM1 S2 KM1 Fuse K3 +24 V XS0 XS1 Z00 Z10 Z20 KM1 Safety relay module MELSEC (QS90SR2S) Power supply Control circuit KM1 Driver Servo amplifier X0 COM0 24G X1 COM1 Z01 Z11 Z21 CN8 Control circuit STO1 S1 or EMG (Note) EMG STO2 STOCOM K3 TOFB1 TOFCOM 0 V TOFB2 20 S1: STO shut-off switch