Appendix E Sto Function Description - IMO HD2 IP Series Instruction Manual

HD2 IP55 High-ingress Protection Series Inverter
Reference standards: IEC 61508-1, IEC 61508-2, IEC 61508-3, IEC 61508-4, IEC 62061, ISO
13849-1, and IEC 61800-5-2
You can enable the safe torque off (STO) function to prevent unexpected startups when the
main power supply of the drive is not switched off. The STO function switches off the drive
output by turning off the drive signals to prevent unexpected startups of the motor (see the
following figure). After the STO function is enabled, you can perform some-time operations
(such as non-electrical cleaning in the lathe industry) and maintain the non-electrical
components of the device without switching off the drive.
Control
circuit

Appendix E STO function description

+24V
UDC+
PWM+
Drive
circuit
PWM-
Switch, relay, etc.
H1
H2
COM
U/V/W
Note:
The contacts of the safety switch must be opened
or closed within 250 ms; and the cable that
connects the inverter to the safety switch cannot be
longer than 25 m.
UDC-
-336