Beckhoff AX2000 Shutdown Braking and Debugging

Beckhoff AX2000 Servo Drive Shutdown Categories and Brake Control Debugging Guide

In the design and maintenance of industrial servo drive systems, how to achieve standard stop and emergency stop functions is the core issue to ensure personal safety and equipment integrity. The Beckhoff AX2000 series digital servo amplifier (rated current 1.5A to 20A) has become a mainstream driving component in many mechanical devices due to its wide voltage input range (3 × 208V to 3 × 480V AC), rich feedback interfaces (Resolvers, SinCos EnDat/HIPERFACE/BISS, incremental encoders), and modular fieldbus expansion capabilities (PROFIBUS, SERCOS, DeviceNet, EtherCAT). However, the safe implementation of its functionality highly depends on the correct implementation of EN 60204 Stop Categories 0/1/2, precise configuration of motor brake control timing, and strict adherence to ground/leakage current specifications. This article will be based on the technical manual of the AX2000 series, and provide an in-depth analysis of the full stack technical points of the servo drive, including mechanical installation, electrical wiring, brake control, shutdown safety circuit, and rapid debugging.

Chapter 1: Product Overview and Core Selection Parameters

1.1 Model System and Power Classification

The AX2000 series is divided into five sub models based on rated output current: AX2001（1.5A）、AX2003（3A）、AX2006（6A）、AX2010（10A）、AX2014（14A）  And AX2020 (20A). Its mechanical width increases with increasing power -70mm for 1.5A to 10A models, 100mm for 14A models, and 120mm for 20A models. All models have a uniform height of 275mm (excluding connectors) and a depth of 265mm.

1.2 Quick check of key electrical parameters

Rated supply voltage: 3 × 230V -10% to 3 × 480V+10% (50/60Hz), can be directly connected to TN or TT systems (grounding center point), with a maximum symmetrical short-circuit current of 5000A.

DC bus voltage: 290V to 675V DC (peak value allowed up to 900V).

Switching frequency: default 8kHz, can be switched to 16kHz when the bus voltage is ≤ 400V (at this time, attention should be paid to doubling the leakage current).

Integrated regenerative braking circuit: Built in regenerative resistor (66 Ω for 1.5/3A and 33 Ω for 6-20A), supports external regenerative resistor expansion, and can achieve balanced distribution of regenerative energy among multiple drivers through parallel connection of DC bus.

Chapter 2: Mechanical Installation and EMC Grounding Specification

2.1 Installation location and heat dissipation requirements

AX2000 must be installed vertically in a closed control cabinet, with an ambient temperature maintained between 0 ° C and+45 ° C (rated operating conditions); 45 ° C to 55 ° C requires a 2.5%/K derating for use. The device is equipped with a forced air cooling fan, and at least 100mm of ventilation space should be reserved at the top and bottom to ensure that cold air enters from the bottom and hot air is discharged from the top. The installation base plate should be made of conductive and unpainted galvanized metal sheet to achieve low impedance discharge of high-frequency interference.

2.2 Grounding System and Leakage Current Management

AX2000 distinguishes multiple grounding areas internally:

AGND: Analog input/output and internal μ C reference ground.

DGND: Digital input/output ground (optically isolated).

XGND: External 24V auxiliary power supply ground (photoelectric and inductive isolation).

PGND: Encoder simulation, RS232, CAN interface ground (optoelectronic isolation).

Key engineering constraints (involving personal safety): Due to the leakage current of equipment to PE typically exceeding 3.5mA (in accordance with EN50178 criteria), PE connections must use dual PE terminals (X0A and X0B in parallel) or PE wires with a cross-sectional area of ≥ 10mm ². The engineering estimation formula for leakage current is:

8kHz switching frequency: I2 leak=n × 20mA+L × 1mA/m

16kHz switching frequency: I2 leak=n × 20mA+L × 2mA/m

(where n=number of drivers, L=total length of motor cables)

Example: Two AX2000+25m motor cables, leakage current at 8kHz=2 × 20mA+25 × 1mA=65mA.

Chapter 3: Motor Brake Control and Power On/Off Timing

3.1 Electrical specifications for brake interface

AX2000 can directly drive the built-in 24V holding brake (maximum 2A) of the motor, but this function is only used for static holding and does not have a personnel safety level. The brake must be activated through the parameter BRAKE=WITH BRAKE, and its action timing is as follows:

When the ENABLE signal is removed or a fault occurs, the internal speed setting value decreases to 0 along a 10ms slope.

When the actual speed is below 5rpm (VELO parameter) or after waiting for a maximum of 5 seconds (EMRGTO), the brake output (X9 terminal B+/B -) is energized and engaged (brake lock).

The output stage was subsequently disabled.

Critical safety warning: Relying solely on the internal electronic control of the AX2000's brake output cannot achieve a safe shutdown in accordance with EN 60204 (Category 0/1). Additional positive action (forced disconnection) safety relay contacts and varistors (Varistor) must be connected in series in the brake circuit for arc extinguishing protection.