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SMC_FB_WASNT_CALLED_DURING_MOTION when enable MC_MoveRelative

Forum: Motion 🇬🇧

Created: 2025-11-02

Updated: 2025-11-03

ducng - 2025-11-02

Hello,
I am using an Inovance PLC to control a servo via EtherCAT. When I enable MC_POWER, the drive switches to Run mode successfully. After that I call MC_MoveRelative, but I get the error SMC_FB_WASNT_CALLED_DURING_MOTION. The servo vibrates but the motor shaft does not move.

I am new to EtherCAT/servo motion control, so I would appreciate any guidance or suggestions for troubleshooting this issue. Thank you in advance for your help.

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gseidel - 2025-11-03

Hi ducng,

please make sure to call all Motion-FBs in the EtherCAT task. In your case, the PLC_PRG should be below the EtherCAT task, not the MainTask.

Best regards,

Georg

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