Calculating Actual Motor Torque and Current with PN Motion Engine

ECAT  (Ethercat) Object 6077 is part of the standard ECAT PDO mappings to KAS from the AKD drive. From the PDO section tab of an AKD axis in an an IDE project.

It provides current in units of units 0.1 percent of drive rated current where a value of 1000  = the drive’s rated current. This value coming over the ECAT can be connected to a project variable by right clicking on the field and mapping an existing or new variable. In the example below the variable A1_TorqueECAT (highlighted in blue)  has been mapped to object 0x6077:

Code can then be added to the IDE project to read the Actual Motor Current and Torque::

 Actual Current Value:  

A1_ActCurrent = ( A1_DriveIcontRating* ANY_TO_LREAL(A1_TorqueECAT))/1000);

Actual Torque Value:

Multiply Actual Current by the motor’s Kt value:
 A1_ActTorque = A1_ActCurrent *A1_MotorKt;

Example:

If an AKM31H  motor (rated for 5.85 amps continuous and a Kt = 0.21 Nm/amp) was being used with a 6 amp continuous AKD drive,  and has a A1TorqueECAT value = 730

A1_ActCurrent = ( A1_DriveIcontRating* ANY_TO_LREAL(A1_TorqueECAT))/1000);

                         = 6*730/1000 = 4.38 amps

and

A1_ActTorque = M1_ A1_ActCurrent *A1_MotorKt

                         = 4.38 * 0.21 = 0.920 Nm