ABB NextMove ESB-2 Fault Diagnosis and Configuration Practice

1. The controller is normal but the motor is not running

Confirm if the 'Drive Enable' signal for the drive has been activated. You can test it by clicking the "Drive Enable" button on the toolbar of Mint WorkBench. If it is enabled by digital output control, check whether the output logic is configured to be high level effective or low level effective; If it is a relay output, note that the normally open contact (NO) is closed when there are no errors. If a stepper motor is used, confirm whether the pulse frequency of the step/direction signal (STEP/DIR) is within the scaling ratio (SCALEFACTOR) range set by the controller.

2. "Flying" or losing control at the moment of power on

Extremely dangerous! Usually caused by poor grounding or feedback polarity errors.

Grounding: It is necessary to ensure that the analog ground (AGND) and digital ground (DGND) between the controller, driver, and motor are reliably grounded.

Feedback polarity: When a positive phase analog command (such as TORQUE (0)=5) is input, the motor shaft should rotate in the positive direction, and the encoder feedback value should increase in the positive direction. If the direction is opposite, the software keywords ENCODEMODE or DACMODE can be used to reverse the logic, or to check if the encoder A and B phases are reversed. In addition, if the ± 10V differential input of the voltage type driver is reversed, it can also cause runaway.

3. Vibration or tracking error during shaft operation

This is a typical tuning problem, which we will elaborate on in detail in the next section.

Servo closed-loop tuning: creating smooth and precise motion control

NextMove ESB-2 supports two mainstream control modes: current (torque) control and speed control. If your drive itself has a speed loop (such as most ABB MicroFlex drives), please use the speed control mode; On the contrary, use the current control mode.

1. Tuning in current control mode (PID regulation)

In this mode, the driver only serves as a power amplifier, and the PID of the position loop is entirely handled by NextMove ESB-2.

KPROP (Proportional Gain): determines the system stiffness. The larger the value, the faster the response, but if it is too high, it can cause overshoot or even oscillation.

KDERIV (Differential Gain): Provides damping. When the system responds with "under damping" (running past the target position and bouncing back, i.e. overshoot), increasing KDERIV can effectively suppress it; When the system is "over damped" (crawling slowly and unable to reach the target position), reduce KDERIV. The ideal state is' critical damping '- quickly reaching the target with almost no overshoot.

KINT (integral gain) and KINTLIMIT: used to eliminate steady-state errors (such as sinking caused by gravity on the vertical axis). When the motor stops slightly in front of the target due to friction, KINT accumulates errors over time and increases output until it tightens. In order to prevent oscillation caused by integral saturation, KINTLIMIT (usually around 5%) must be set to limit the upper limit of integral action.

KVEl (Speed Feedback Gain): Used to increase damping, reduce vibration during rapid motion, and allow you to set higher KPROP.

2. Tuning in speed control mode (feedforward prediction)

If the driver itself closes the speed loop, NextMove ESB-2 only needs to perform position loop control. At this point, KDERIV and KVEl are usually set to 0, and the key is to set KVELFF (speed feedforward gain).

The function of KVELFF is equivalent to "an experienced driver looking at the road while driving". It does not rely on error feedback, but directly provides speed instructions in advance based on trajectory planning, greatly reducing tracking errors.

The formula for calculating KVELFF is usually 2048 ÷ (motor speed per minute/60 x 1ms sampling period x encoder count per revolution). For example, a 1000 line encoder (4000 counts after orthogonal) and a 3000 rpm motor can calculate a KVELF of approximately 10.24. After entering this value, run a trapezoidal speed curve. If the actual speed is slightly behind the commanded speed, fine tune and increase the value; If ahead, then decrease. After adjustment, slightly increase KPROP (such as starting from 0.1) to tighten the position error.

Status indicator lights and underlying diagnostic techniques

If the debugging software is not connected, the 7-segment digital tube of NextMove ESB-2 is the only source of information. When running normally, it displays the node number. After selecting a specific axis through the Mint keyword LED, it will display various status characters:

-Drive Disable is the most common state that requires sending an enable signal.

8: The axis has been enabled and is in a ready or running state.

P: Performing point-to-point position movement.

J: Jog is currently in progress.

F: There is a following error. This may be due to excessive load, high acceleration settings, or inappropriate tuning parameters.

E: General errors (such as hardware failures or software errors), specific code needs to refer to Mint WorkBench's Error Log or AXISERROR keyword.