146
8 USING STO FUNCTION
8.3 Connection example
External I/O signal connection example using an external safety
relay unit
This connection is for source interfaces. For the other I/O signals, refer to the following connection examples.
Page 48 Example I/O signal connections
This connection example complies with the requirements up to ISO/EN ISO 13849-1:2015 category 3 PL e and IEC/EN 62061
SIL CL 3.
For details, refer to the safety relay module user's manual.
*1 To enable "Emergency switching off" for the shut-off by the STO function of the drive unit, change S1 to EMG. The stop category at this
time is "0".
Page 144 Precautions for compliance with stop category 1 (IEC/EN 60204-1)
24 V
0 V
S2
K3
+24V
XS0
XS1
Z00 Z10 Z20
X0
COM0
24G
X1
COM1
Z01 Z11 Z21
K3
CN8
KM1
CN3
EM1
EM2
STO1
TOFB1
TOFCOM
TOFB2
STO2
STOCOM
M
KM1
KM1
EMG
S4
S3
Fuse
Safety relay
module
MELSEC
(QS90SR2S)
Power
supply
Control
circuit
Control circuit
S1 or
EMG
*1
S1: STO shut-off switch (STO switch)
S2: Start switch (STO release switch)
S3: ON switch S4: OFF switch
KM1: Magnetic contactor
K3: Safety relay
EMG: Emergency stop switch
or
Servo motor
Drive unit