After 1 year in operation, the drive shows a message that a yearly test must be performed. Power cycle the drive by disconnecting andthen reconnecting the supply voltage. Activate the used inputs on the safety option and check that they function correctly.3.6.10 Safety Parameter SettingsFactory setting for both digital inputs is Safe Torque Off, meaning that the Safe Output S37 is in low state.At the first power-up, the option shows Blank Initial State.Properties of safety parameters• They are kept separate for each monitoring channel.• During start-up, a checksum (cyclic redundancy check, CRC) over the safety parameters is generated and checked. The parametersare stored on the non-volatile memory on the option.A reset of the safety parameters to the factory setting can be executed via the MCT 10 Set-up Software.N O T I C EIf the safety option is reinstalled in another drive, all safety parameters can be selected either from the safety option or from thedrive in which the option is now installed. Always perform a commissioning test to ensure the correct functionality.3.6.11 Encoder InterfaceN O T I C ESome of the diagnostics performed on the encoder signals require motion to detect faults. Make sure that motion occurs atleast once every 12 months.To detect the standstill or the motor speed, the speed (frequency) is measured using a TTL encoder (MCB 150), an HTL encoder (MCB151), or a PNP proximity switch (MCB 151). The HTL encoder uses 2 signal tracks, A and B. TTL encoders use 4 signal tracks A, B, andtheir inverted tracks nA, nB.Use twisted-pair, individually shielded cable to connect encoders to the safety option.3.7 Limitations3.7.1 Exceeded Limit Value and Internal Errors• Exceeding set limit values activate the stop braking ramp.• Any internal error on the safety option or drive activates the safety function STO. The drive coasts the motor.Internal errors always result in a fault, requiring a power cycle of the drive to reset the failure. Alternatively, use parameter 42-90 RestartSafe Option to restart the safety option after internal failure without power cycling the drive.3.7.2 Compatibility between Safety and Drive FunctionThe safety option is compatible with all VLT AutomationDrive FC 302 drives.Functions and Systems OverviewInstallation Guide | VLT® Safety Option MCB 150/151AQ279747441421en-000101 / 130R0292 | 35Danfoss A/S © 2018.09