CANOPEN SYNC timeout after enable Operation

I am a newbie in CANOPEN. I wrote a program that read actual position via PDO1 (default is statusword + actual position).

void canopen_init() {
// code1 setup PDO mapping
nmtPreOperation();
disablePDO(PDO_TX1_CONFIG_COMM);
setTransmissionTypePDO(PDO_TX1_CONFIG_COMM, 1);
setInhibitTimePDO(PDO_TX1_CONFIG_COMM, 0);
setEventTimePDO(PDO_TX1_CONFIG_COMM, 0);
enablePDO(PDO_TX1_CONFIG_COMM);

setCyclePeriod(1000);
setSyncWindow(100);

//code 2: enable OPeration
readyToSwitchOn();
switchOn();
enableOperation();    
motionStart();

// code 3
nmtActiveNode();
}


int main (void) {
  canopen_init();   
  while {
    delay_ms(1);
    send_sync();
  }
} 

If I remove "code 2" (the servo is in Switch_on_disable status), i can read position each time sync send. But if i use "code 2", the driver has error "sync frame timeout". I dont know driver has problem or my code has problem. Does my code has problem? thank you!

Problem fixed. Due to much EMI from servo, that make my controller didn't work properly. After isolating, it worked very well :)!