STMBL v4 Servo Drives
Overview
Open source servo drives made by Rene Hopf. The name STMBL comes from "STM32" and "BrushLess".
Software
The servo drive can be configured and debugged using it's Micro USB connector, which provides a USB CDC (UART/serial) interface. You can using any terminal emulator such as PuTTY, minicom, etc. However, to easily configure the non-volatile settings and plot real-time oscilloscope data, there is dedicated software:
https://github.com/STMBL/QtServoterm
Wiring
There are three RJ45 jacks, one intended for control signals going to the drive, and two for feedback from the servo. In most cases only the first of the two feedback ports will be used, but in some cases there are multiple types of feedback, such as an ABZ encoder along with UVW hall sensors.
Control
| RJ45 Pin | RJ45 Color | Step/Dir | Mesa SS |
|---|---|---|---|
| 1 | orange-stripe | STEP+ | RX- |
| 2 | orange | STEP- | RX+ |
| 3 | green-stripe | DIR+ | TX- |
| 4 | blue | FAULT- | GND |
| 5 | blue-stripe | FAULT+ | GND |
| 6 | green | DIR- | TX+ |
| 7 | brown-stripe | EN+ | VCC |
| 8 | brown | EN- | VCC |
NOTE: the STMBL drives do not actually use the VCC/GND connections, they just end up driving differential transceivers (with non-differential signals). The STMBL expects to have a common logic ground with the Mesa card.
Mesa Smart Serial RJ45 Pinout:
| RJ45 Pin | Function | Direction |
|---|---|---|
| 1 | TX- | Mesa → STMBL |
| 2 | TX+ | Mesa → STMBL |
| 3 | RX- | Mesa ← STMBL |
| 4 | GND | Mesa → STMBL |
| 5 | GND | Mesa → STMBL |
| 6 | RX+ | Mesa ← STMBL |
| 7 | +5V | Mesa → STMBL |
| 8 | +5V | Mesa → STMBL |
Mesa Smart Serial Terminal Block Pinout:
| TB Pin | RJ45 Color | Function | Direction |
|---|---|---|---|
| 1 | blue | GND | Mesa → STMBL |
| 2 | blue-stripe | GND | Mesa → STMBL |
| 3 | green | RX+ | Mesa ← STMBL |
| 4 | green-stripe | RX- | Mesa ← STMBL |
| 5 | orange | TX+ | Mesa → STMBL |
| 6 | orange-stripe | TX- | Mesa → STMBL |
| 7 | brown-stripe | +5V | Mesa → STMBL |
| 8 | brown | +5V | Mesa → STMBL |
Feedback
| RJ45 Pin | RJ45 Color | Resolver | 1Vpp | UVW | Quad. | RS-485 | RS-422 | UART | USART | UART HD | USART HD | SPI | SPI HD |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | orange-stripe | Sin+ | Sin+ | U+ | A+ | A | RX+ | RX+ | MISO+ | CS+ | |||
| 2 | orange | Sin- | Sin- | U- | A- | B | RX- | RX- | MISO- | CS- | |||
| 3 | green-stripe | Cos+ | Cos+ | V+ | B+ | CLK+ | CLK+ | CLK+ | CLK+ | ||||
| 4 | blue | Ref- | W- | Z- | B | Z | TX- | TX- | TX/RX- | TX/RX- | MOSI- | MOSI- | |
| 5 | blue-stripe | Ref+ | W+ | Z+ | A | Y | TX+ | TX+ | TX/RX+ | TX/RX+ | MOSI+ | MOSI+ | |
| 6 | green | Cos- | Cos- | V- | B- | CLK- | CLK- | CLK- | CLK- | ||||
| 7 | brown-stripe | AIN | VCC | VCC | VCC | VCC | VCC | VCC | VCC | VCC | VCC | VCC | VCC |
| 8 | brown | GND | GND | GND | GND | GND | GND | GND | GND | GND | GND | GND | GND |
Replacement Parts
Terminal Blocks
| STMBL Name | Part Name | DigiKey Part # |
|---|---|---|
| P2 "PTC", P3 "Logic Power", P15 "Alt. CMD" | Phoenix Contact 1840366 | 277-2417-ND |
| P5 "Outputs", P9 "Inputs" | Phoenix Contact 1840421 | 277-5715-ND |
| P6 "Motor DC Input" | Phoenix Contact 1911965 | 277-9026-ND |
| P8 "Motor 3-phase Output" | Phoenix Contact 1911978 | 277-11013-ND |
Online Resources
https://github.com/rene-dev/stmbl
https://github.com/rene-dev/stmbl/wiki/Pinouts
https://github.com/rene-dev/stmbl/blob/master/docs/src/Getting%20Started.adoc