Determining the electrical commutation offset

Execute the command P-0-0166 (see section “Checking the direction of rotation”). To determine the commutation offset we need the current value from parameter P-0-0057 and the current value from parameter P-0-0167:

Read the value for “Commutation position difference”. Subtract this value from the value in P-0-0057 “Electrical commutation offset”. If the result is positive, this is the new value for P-0-0057. If the result is negative, add 360°.

Sample:

90° - 178.57° = -88.57°

-88.57° + 360° = 271° (fractions can be neglected.)

The result is the new value for P-0-0057 “Electrical commutation offset”. Enter the value at SetValue and confirm with <Enter>. Confirm the message that is displayed with <Yes>.

Pressing the download button (red circle) activates the new value immediately.

The value is displayed in the setting “ActValue” after the download is complete. Execute command P-0-0166 again!

The value for “Commutation position difference” should now lie within the range: 355 … 360 = 0 … 5.

If this value is displayed you have successfully completed the commutation search! The offset value has already been adopted into the startup list with the download button.

To use the commutation angle, the “Commutation mode” must be changed in parameter P-0-0150:

Change the entry “Commutation mode” to “3:Adjustable offset”. Then reactivate the TwinCAT configuration.

After changing the “commutation mode” once, this method has the advantage (compared with the mechanical offset) that the offset (P-0-0057) can be changed at any time without having to restart the system.