Various (filtered) feedback tracking error values.  The error terms are computed as (setpoint command - actual value).

The calculated intermediate torque values generated by the feedback compensator. The PID torque (DataIDs 12325, 12326, 12327) + accel error torque (DataID 12329) + filtered feedforward torque (DataID 12331) + gravity compensation torque (12443) compose the final output torque command, which is fed into the amplifier and displayed as the "Compensator output torque" (DataID 12304).

See DataID 12338 for a sum of just the feedback torques, possibly limited.

See DataID 12341 for a sum of just the feedforward torques.

The extrapolated position error is the sum of the current position tracking error and the predicted position tracking error. The predicted position tracking error is calculated via the velocity tracking error multiplied by the prediction window (DataID 10325). Note that this value is used for the position in-range check.

External feedforward torque, which comes from system's synchronous command.  This torque is currently only used as part of a special mode where the controller receives position and torque set point commands from an external computer via a custom Ethernet protocol. 

(Split-axis)  This is a special feedback term that is only valid for motors that are controlled in split-axis mode.  This value is the result of multiplying the cross-coupling gain factor by the filtered difference in the actual position of the two split-axis motors.

(Split-axis)  This is the difference in the actual position of the two split-axis motors.

(Split-axis)  This is the filtered difference in the actual position of the two split-axis motors.  This term is multiplied times the "Split axis cross-coupling gain" (DataID 10339) to compute the "Split axis cross-coupling torque, tcnt" (DataID 12334).

For kinematic modules that generate Dynamic Feedforward torques, this parameter indicates the DFF torque command that was received from the Trajectory Generator and was added to the position loop compensator, in tcnts.  The "Feedforward torque" (DataID 12330) does not include DFF.  DFF is added to DataID 12330 before the combined value goes through the "Feedforward SPR filter" (DataID 10328) and the "Feedforward torque rate limit" (DataID 10348).

If the servo is not in position control mode, this value will be zero.

In comparison, the "Dynamic feedforward torque command" (DataID 12406) displays the value of the DFF command received from the Trajectory Generator and will be valid even if the servo is in torque control or some other mode.

If a servo is in position control mode, this parameter provides just the portion of the torque output command generated by the PID feedback terms.  So, it is essentially the value of the "Compensator output torque" (DataID 12304) minus the sum of the "Dynamic feedforward torque" (DataID 12337) and the "Filtered feedforward torque" (DataID 12331).

This value is limited by the "Max positive/negative torque limit for PID feedback" (10351,10352).

This parameter displays the derivative gain value (Kd) that is currently in use.  For most systems, this value is constant and is equal to "Derivative gain, Kd" (10333).  However, if Kd gain scheduling is active by setting "Kd gain schedule, gain at zero speed" (DataID 10363) and "Kd gain schedule, activate below speed" (10364), the active value of Kd is dynamically modified as a function of the motor's speed.  In this case, the value of the "Active derivative gain" parameter will change and will indicate the value of Kd that is instantaneously in effect.

This parameter displays the sum of the "Filtered feedforward torque" (12331) and the "Gravity compensation torque" (12443).  For axes with gravity loading, this parameter contains all of the feedforward torques that will be added to the PID feedback except for the Dynamic feedforward.