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

Alternate replacement connector information:

Name	Connector	PCB Header
Motor DC Power Input	Phoenix Contact 1757019 (12A) Phoenix Contact 1911965 (16A) Amphenol Anytek TJ0251530000G (12A) Würth Elektronik 691351500002 (12A)	Phoenix Contact 1757242 (12A) Phoenix Contact 1923869 (16A)
Motor DC Power Output	Phoenix Contact 1757022 (12A) Phoenix Contact 1911978 (16A) Amphenol Anytek TJ0351530000G (12A)	Phoenix Contact 1757255 (12A) Phoenix Contact 1923872 (16A)
Logic Power Alt. Cmd. Thermistor	Phoenix Contact 1840366 Amphenol Anytek TJ0211530000G	Phoenix Contact 1844210
Inputs Outputs	Phoenix Contact 1840405 Amphenol Anytek E20611300000G	Phoenix Contact 1844252