Bonfiglioli BMD Servo Motor Selection and Configuration Guide

SICK SKS/SKM series (ENB3/ENB4): Supports Hiperface protocol, with a maximum single loop resolution of 15 bits.

Engineering tip: When choosing an optical encoder, it is important to pay attention to its anti vibration ability. For example, the comparison on page 50 of the manual shows that Heidenhain ENB1/ENB2 has a vibration resistance of 200 m/s ², while SICK ENB3/ENB4 has a resistance of 50g (approximately 490 m/s ²). If applied in situations with extremely high impact loads, priority should be given to selecting models with higher impact resistance specifications.

3. New Inductive and Capacitive Encoders

In response to the pursuit of compact space and high robustness, BMD has introduced bearingless encoder technology:

Heidenhain EQN1131 (ENB8): Based on the principle of inductive measurement, supports EnDat 2.2 protocol, and has functional safety features. Its rotor inertia is only 0.30x10 ⁻⁶ kgm ², which has minimal impact on the dynamic response of the motor.

SICK EEM series (ENB9/ENB12): based on capacitive measurement principle, supporting Hiperface DSL protocol. The ENB12 model also supports functional safety (SIL level).

Selection suggestion: For applications that require SIL (Safety Integrity Level) certification for Safety Torque Off (STO) or Safety Stop 1 (SS1) functions, it is recommended to prioritize ENB8 (EnDat 2.2), ENB10/ENB11/ENB12 (Hiperface DSL), and connect the drive system through the EMA-SABS-21 or EMA-SABS-11 safety modules recommended by Bonfiglioli.

Braking, inertia matching, and forced air cooling options

1. Holding Brake - F24 option

The brake of BMD motor is of power-off braking type, with a power supply voltage of 24V DC. The detailed braking parameters are listed on page 52 of the manual.

Key data: For BMD 170, the braking torque is as high as 36 Nm, but the response time (Engage time+Release time) is approximately 11ms.

Engineering red line: The manual clearly states that this brake is only used for holding braking and is strictly prohibited from being used for dynamic braking, except in emergency situations such as main power failure.

2. Additional Inertia (F1 option)

In high load inertia matching scenarios, a motor body with too little inertia may cause system response oscillations. The F1 option solves this problem by increasing the flywheel mass. According to page 53 of the manual, after adding a flywheel to BMD 145, the inertia increases by 36x10 ⁻⁴ kgm ² and the mass increases by 5.0kg. This can bring the inertia ratio of the motor to the load into a more controllable range (usually recommended 1:5 to 1:10).

3. Forced Ventilation (options such as V1R/V1S)

Only available for BMD 145 and BMD 170. When natural cooling cannot meet the continuous high torque output of S1, forced air cooling (IC416) can increase the locked rotor torque to 60 Nm (page 17 of the manual). It is worth noting that page 54 of the manual provides the ordering code for the retrofit kit (such as 19MOT0013), which allows users to upgrade the standard motor to forced air cooling on site, but requires additional machining of 8 threaded holes on the casing.

Engineering Wiring Practice: Servocables and Connector Layout

The proportion of wiring errors in servo system failures is extremely high. The BMD manual provides extremely detailed pin definitions and cable selection tables on pages 56-67.

1. Principle of Separation of Power and Signal

Power Cable: Orange sheath, compliant with DESINA standards. For motors with feedback, use 6-core (U/V/W+ground+brake+/-) connectors; For the Sensorless version, an 8-pin connector is used (page 56 of the manual).

Signal Cable: Green sheath. Page 63 of the manual provides a detailed distinction between the plug definitions of Resolver (12 pin) and EnDat (17 pin). For example, the Sin+/Sin - of the Resolver corresponds to pins 2 and 1, while the Data+/Data - of EnDat corresponds to pins 14 and 17.

2. The rise of hybrid cables

For motors using Hiperface DSL (ENB9... ENB12) and EnDat 2.2 (ENB8), hybrid connection is supported, where the power line and encoder signal line are integrated into the same cable.

The mixed plug layout of BMD 170 is shown on page 59 of the manual, which has the advantage of significantly reducing the number of interfaces at the motor end, which is crucial for compact installation space with IP67 protection level. When choosing a hybrid cable (such as OCM XX CD1/CO2), it should be noted that its D-SUB pin definition is specifically designed for Bonfiglioli's EM-SABS-11/21 interface module and is not compatible with general third-party drivers. This must be strictly checked during system integration.

3. Bending life of cables

On page 61 of the manual, it is stated that standard servo cables are suitable for dynamic laying, with a bending frequency of no less than 10 times and a maximum acceleration of 15 m/s ². In robot or high-speed truss applications, it is necessary to calculate the bending radius of the cable (>10 times the outer diameter of the cable) and the speed of the drag chain, otherwise the shielding layer will break and the encoder signal will be lost.

Thermal protection and nameplate interpretation