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under Pollution Degree 3 environment the safety circuit that implements the STO functional safety function
will not reduce its performance. Therefore, the STO function operation can be ensured even under Pollution
Degree 3.
- To bring the inverter into compliance with Functional Safety Standard, it is necessary to bring it into
compliance with European Standards EN61800-5-1 and EN61800-3.
- This Safe Torque Off (STO) function coasts the motor to a stop.
- In case of diagnostics with a safe PLC, short pulses with a duration less than 1 ms should be input to
terminals [EN1] and [EN2].
- The safety shutdown circuit between input terminals [EN1] and [EN2] sections and inverter's output
shutdown section is a redundant circuit so that an occurrence of a single fault does not prevent the Safe
Torque Off (STO) function.
If a single fault is detected in the safety shutdown circuit, the inverter coasts the motor to a stop even with
the terminal [EN1]-[PLC] and [EN2]-[PLC] states being ON, as well as outputting an alarm to external
equipment. Note that the alarm output function is not guaranteed to all of single faults. It is compliant with
EN ISO13849-1 Cat. 3 PL=e.
- This Safe Torque Off (STO) function may not completely shut off the power supply to the motor electrically.
Before starting wiring or maintenance jobs, be sure to disconnect the input power to the inverter and wait at
least 5 minutes.
3) Test of Safe Torque Off (STO) function
- [EN1]/[EN2] and [PLC] must be turned off for diagnostics at least one time per hour. Then [EN1]/[EN2] and
[PLC] must be kept off for at least 2 seconds.
- Main power supply must be shut off (auxiliary power supply of the control circuit can be supplied) at least
one time per one day.
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