8-16 Safe Torque OffAC30 series Variable Speed InverterSTO Trip AnnunciationThe GKP will display a STO trip message when STO becomes active, i.e. STO prevents the drive from starting, thus:GKP DisplayThis message is displayed immediately if, on starting the drive or whilst the drive is running:• One or both STO user inputs X10/01 or X10/03 is low when the user attempts to start the drive, or• One or both STO user inputs X10/01 or X10/03 goes low while the drive is running, or• The inverter has detected a fault in the STO circuit.Note: an out-of-box inverter will report this trip if the drive, as supplied, has no connections to X10 when it is first started. Appropriateconnections must be made to X10 to prevent this trip from occurring, as described elsewhere in this chapter. The user must decide if STO isto be permanently inactive, or to make use of the STO feature. If the STO feature is not required, see the “Applications that do not requireSTO function” section on page 8-19.STO is inserted into the trips history buffer (see Chapter 10 Trips & Fault Finding) if STO is active when the drive is commanded to start or ifSTO becomes active while the drive is running, indicating an abnormal condition. The trips history buffer is not updated if STO becomesactive while the drive is not running.Note: The normal method of operation is for STO to become active while the drive is not running and the motor is stationary.Appropriate, application specific risk assessment is necessary when STO is activated on rotating motors, moving loads or when externalforces such as gravitation or inertial loads act on the motor.**** TRIPPED ****SAFE TORQUE OFF
