RW[5.15.15]Profinet system failure

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MRGREEI China
Options:
645-1 French
709-x DeviceNet
709-2/709-5 Master/Slave Dual
711-1 PROFIBUS DP m/s
888-2 PROFINET m/s SW
608-1 World Zones
613-1 Collision Detection
623-1 Multitasking
630-1 Servo Tool Change
635-5 Spot Servo Equalizing
Weld Timer Configuration Options
709-x DeviceNet
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Profinet bus unplugging the network cable will directly cause system failure.
No error message appears, only internal errors.
Tsksup.c 297 Exception: task delay_medium vect 14
pc=0x0; sr=0