But if the motors are rotating at high speeds, can we use some kind of interrupt to get the actual position values, at the same time for both axis? 

Hi there,

gotta support Jacek, his answer is still valid.

The motion control technology objects (TOs) have specific OBs which read the according process image with the input data, process it, update the DBs of the TOs, ..., and in the end write the process image with output data. The OB that reads and writes the process image and actualizes the TODB is OB MC-Servo.

So using - like Jacek stated - OB MC-PostServo to read the TOs values is the right place to do it. PostServo is called right when MC-Servo is finished, so directly when the TODBs got actualized with new data. T

I just want to add: Don't do too much in OB MC-PostServo, try to keep it small and fast. Otherwise you might get overflows (i.e. Servo + PostServo OB call occurred again before last execution was finished), which results in PLC STOP. So take care to not put too much code in it, perhaps check with RT_Info instruction if the cycle you parametrized at the Servo OB is still long enough.

Closer information on the motion runtime execution and also the overflow issue are to be found here: https://support.industry.siemens.com/cs/ww/en/view/109812056/159504888843

Regards,
daviso