Bernecker & Rainer (B&R) ACOPOS P3 – Teardown

B&R ACOPOS P3 is a compact, efficient and precise servo drive with integrated safety functions, ideal for use in automotive, printing, packaging, handling and robotics, or any process demanding extreme precision and speed. An impressive reduction in size, of just under 70%, where heat dissipation would have previously been problematic, has been made possible with significant advances in both transistor and processor technology. These new components are smaller, cooler, faster and more precise. 

Offered in 10 models, the ACOPOS P3 is available in 1 to 3-axis drive with power ranges from 0.6 to 18kW, or 1.6 to 44, along with several other options, varying by model. The 3-axis drive is as compact as a conventional 1-axis drive, reducing space requirement by 69% with maximum power density. It can control extremely fast movements with precision by using short cycle time of current, speed and position measurements. 

The ACOPOS P3 is among the fastest drives available, with sampling times of 50 µs for current, speed and position control, made possible by advances in both hardware and algorithms. This is a substantial improvement over the 400 µs update rate commonly found in drives manufactured only a few, short years ago. With these faster sampling speeds, virtual senor technology is now possible, and servo motors may be operated without an encoder. The open loop feedback is very similar to that found in variable frequency drives.

The ACOPOS P3 compiles to safety regulations SIL3/ PL e/ Cat, and may be ordered in either standard or safeMotion configurations. The integrated safety functions include STO, SOS and the new SLT (Safety Limited Torque) and run on virtual safety controller on the PLC Ethernet network.  



Model: 8EI8X8HWT10.XXXX-1. ACOPOS P3, 3-axis 200-480 VAC, 8.8 A servo drive. 

External and Enclosure 

  • Size 66mm x 374mm x 261mm and weight 4kg. 
  • IP20 protection for pollution degree 2 environment with operating temperature up to 55°C.


Main Controller Board


  • PWM motor control and communication: Altera Cyclone IV EP4CGX50Cf23I7N FPGA. Low power and cost FPGA with 50K logic elements for PWM, Sigma-delta ADC and DC-link control interface. 8 High speed transceivers and dedicated hard IP for PCI Express and wide range of protocol support, including Ethernet.


Power Electronics Board

Power Electronics Board Block Diagram

  • Rectifier & Inverter
    • Infineon  FP35R12W2T4_B11(1-axis), 1200V/35A IGBT4 with Rectifier in EasyPIMTM 2B Module.
    • Infineon  FS35R12W1T4_B11 (2pcs for 2-axis), 1200V/35A IGBT4 in  EasyPACK Module.


  • Isolation: Broadcom (Avago Technologies)
    • QCPL-325J (18pcs for 3-axis. 1pcs for braking). Customized IGBT gate drive optocoupler with integrated protection and feedback.
    • ACPL-798J (6pcs for 3-axis, 2pcs for bus voltage). Optically isolated Sigma-Delta modulator with LVDS Interface, external clock.


  • Shunt Current Sensing: Vishay Dale R01F (12pcs for 3-axis). 10mΩ shunt resistors.


  • Isolated Switching Power Supply: Pulse Electronics PH9392NL (3pcs for 3 axis). Customized DC/DC converter.


  • Inrush-current Limiter: EPCOS  J109 (2pcs). PTC thermistor as inrush current limiter.


  • DC Bus Bulk Capacitor: EPCOS B43547-A5477 (4pcs). 450V/470µF electrolytic capacitor‎.


User Interface and Communication Board


  • User Interface controller:  Freescale MCIMX6S7CVM08AC, i.MX 6 series 32-bit MPU, ARM Cortex-A9 core, 800MHz, MAPBGA 624
  • Power Management IC: Freescale MMPF0100. Power supplies for the entire embedded i.MX 6 MCU.
  • Memory:
    •  Micron DDR2/3 SDRAM.
    • Spansion S25FL245SA. 256Mb Qual SPI NOR Flash.
  • Ethernet Communication: TI DP83848x (2pcs). PHYTER Mini / LS Single Port 10/100 MB/s Ethernet Transceiver.


This drive is ideal for an array of precision and complex applications. Because not all implementations are subject to CE/EMC requirements, the filter is no longer built-in. However, external filters and other safety features may be added, as needed. This scalability of hardware facilitates the connection of two, three-axis units tied into DC busses and daisy chaining line power, for painless expansion.


Designers will appreciate the minimal space requirement, given the smaller footprint of the ACOPOS P3, and reduced space necessary for filters, and fuses or circuit breakers. This all provides for a much smaller control cabinet, allowing for more options to locate it and taking up significantly less space on production floors, where real estate may be at a premium. Single cable motor technology makes for a cleaner profile and simple installation.

Extraordinarily versatile, the ACOPOS P3 is equally suited for standard discrete equipment, CNC machinery or robotics application – all may be driven with the same hardware. Designers need only to add a configuration, rather than programming since new software components are configured graphically.

Engineers seeking a trim, cost-effective, and precise servo drive should absolutely consider the B&R ACOPOS P3 for their next build.

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