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The product Kamilla is unboxing in this episode is the EVALKIT-ROBOT-1 reference design kit (201-4458) for brushless servo control that STMicroelectronics has developed in collaboration with Maxon.
The kit has been designed as a compact, plug-and-play stand-alone solution for evaluating STSPIN32 family of motor driver ICs and it includes both electronics and motor in the box.
The target application of EVALKIT-ROBOT-1 is industrial robotics automation, where reliable and high-precision position and speed control is of paramount importance.
Firstly, there is Maxon EC-i 40 100W 3-phase brushless DC motor that comes with in-built 1024-pulse incremental encoder and hall sensor. The nominal voltage for best system performance with this motor is 36V. Other important specifications, including no-load speed and stall torque are 4550rpm and 3160mNm, respectively.
STSPIN32F0A Motor Driver IC
Let’s quickly discuss the internal structure of STSPIN32F0A motor controller. The uniqueness of this IC is that it integrates an advanced BLDC controller, a 32-bit Cortex M0 core MCU and analog peripherals, such as opamps, comparators and voltage regulators, into a single 7mm QFN package.
The operating voltage range of this motor controller is from 6.6V up to 45V. The M0 core supports up to 48MHz of clock frequency, 32kB Flash and 4kB SRAM.
A triple half-bridge gate driver can drive power MOSFETs with a current capability of 600 mA.
There are three operational amplifiers available for signal conditioning and a single comparator for overcurrent protection.
The STSPIN32F0A also integrates the full power management circuitry consisting of the switching regulator and LDO to provide the 3.3V to the microcontroller and supply voltage to the driver.
Lastly, Field Oriented Control (FOC) FW flashed inside STSPIN32F0A implementing closed-loop robust high precision control.
STL7DN6LF3 power MOSFETs
Power MOSFETs that used in the control board are STL7DN6LF3 Dual N-channel MOSFETs in PowerFLAT™ 5x6 Dual Island package. Typical drain-source on-resistance for this MOSFET is 35mΩ.
RS485 / MODBUS
The servo control can be controlled via MODBUS communication protocol through an RS-485 connection. MODBUS is a widely used protocol in industrial automation. With EVALKIT-ROBOT-1, you just need one cable to connect the board to your PC and a MODBUS master application installed on your PC.
Please note that the servo control board is designed and intended to be used only with Maxon motor provided in the kit. To get started, you will need the following hardware:
- 36V / 120W DC power supply
- RS485 2-wire serial port
- Communication software based on MODBUS protocol
- In case you decide to work with ST-LINK instead of MODBUS:
- 20-pin to 10-pin adapter for JTAG/SWD programmers
For related documentation, check out the kit’s page, but we have also listed relevant resources below:
How to read Maxon motor datasheets?
Maxon’s ENX 16 EASY encoder datasheet
3-phase Field Oriented Control (FOC)
Getting started with the EVALKIT-ROBOT-1