Delta VFD-ED Series, User Manual

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Ch16 Safe Torque Off Function | VFD-ED
16-3
16-2 Description of STO’s Functions
The STO (Safe Torque Off) function is to cut off the motor’s power supply to prevent the motor from
producing torque force. The STO function is run by two independent hardware circuits to control the drive
signals emitted by the motor’s current, and then to cut off motor drive’s power module output in order to
safely stop the motor drive.
The following table describes the terminal functions.
Table 1: Terminal Function Descriptions
Signal Channel Status of Photo Coupler
STO
Signal
STO1–SCM1 ON (High) ON (High) OFF (Low) OFF (Low)
STO2–SCM2 ON (High) OFF (Low) ON (High) OFF (Low)
Drive Output Status Ready
STL2 mode
(Torque output off)
STL1 mode
(Torque output off)
STO mode
(Torque output Off)
 STO is Safe Torque Off
 STL1–STL3 means an STO internal hardware error.
 STL3 means STO1–SCM1 and STO2–SCM2 has an internal circuit error.
 STO1–SCM1 ON (High): means STO1–SCM1 has connection to a +24 V
DC
power supply.
 STO2–SCM2 ON (High): means STO2–SCM2 has connection to a +24 V
DC
power supply.
 STO1–SCM1 OFF (Low): means STO1–SCM1 has no connection to a +24 V
DC
power supply.
 STO2–SCM2 OFF (Low): means STO2–SCM2 has no connection to a +24 V
DC
power supply.