This four-axis synchronized CNC engraving machine uses an ESP32 microcontroller to coordinate independent stepper motors on X, Y (dual motors), and Z axes. The build combines Leadshine DM556 stepper drivers with 42CM06D motors, a Mean Well 350W power supply, and signal conditioning via 2N3904 transistors to create a compact routing and engraving platform.
This guide provides a complete wiring diagram, parts list, and step-by-step assembly instructions for integrating the motor drivers, power distribution, and control electronics. The included firmware enables basic jog commands via USB serial interface (no G-code required), allowing makers to test axis movement and calibrate the machine before adding advanced motion control or CAM software.
Wiring diagram
Gather all the parts
Assemble it in 5 steps
1. 先脱开机械负载
断电，四台电机先不连接丝杆或皮带。固定电机本体，轴上不要装刀具。该项目仅验线，不可加工。
- 无限位、无归零、无硬件急停；禁止连接主轴或带负载试车。
2. 安装转接板
MRD076A只是接线转接板。核对开发板与插座方向和全部电源脚，断电用万用表确认标为4至11的端子分别通向对应GPIO，而不是按排针位置数。无法确认就不要插板上电。ESP32只用USB供电。
- 24V接入MRD076A会烧毁开发板。不要同时向5V端子接第二路电源。
3. 制作八路信号接口
每路使用一只2N3904、一只1kΩ基极串联电阻和一只10kΩ基极到地电阻。GPIO经1kΩ到B；E到ESP32地；C到对应PUL-或DIR-；PUL+和DIR+到USB的5V。使用焊接板固定，按购买厂商资料识别B/C/E，不猜腿序。
- X用GPIO4/5，Y1用6/7，Y2用8/9，Z用10/11，前者为脉冲、后者为方向。接口不是隔离板；DM556内部提供光耦输入。
4. 接电机与驱动器
断电测出每台电机的两对线圈，分别接A+/A-和B+/B-。每台电机单独一个DM556。ENA两端均不接。按本机说明设置5V控制输入、单脉冲STEP/DIR模式；初测选择最低电流档，细分建议四台均为1600脉冲/圈（若本机支持）。
- 不得设5.6A；正式电流需区分峰值与有效值并匹配2.5A/相电机。禁止带电插拔电机。不同DM556版本拨码不同，不照抄开关位置。
5. 完成受保护的电源接线
由电工完成L/N/FG接线、保护地与金属箱机架连接、交流保护、端子防触碰和导线固定。四个驱动器并联接24V，按实际线径完成支路保护后再上电；24V不经过MRD076A。此处6A是暂估直流总负载，不是保险选型值。
- 市电有致命触电风险；未完成保护不得上电。先接通USB控制电源，再接24V。停止脉冲不切断驱动电流；紧急情况使用安全可接近的电机电源断电装置。
Review all connections
1. Connections between "adapter" and "ESP32"
2. Connections between "psu" and "ESP32"
3. Connections between "drv_x" and "ESP32"
4. Connections between "motor_x" and "ESP32"
5. Connections between "rb_x_step" and "ESP32"
6. Connections between "pd_x_step" and "ESP32"
7. Connections between "q_x_step" and "ESP32"
8. Connections between "rb_x_dir" and "ESP32"
9. Connections between "pd_x_dir" and "ESP32"
10. Connections between "q_x_dir" and "ESP32"
11. Connections between "drv_y1" and "ESP32"
12. Connections between "motor_y1" and "ESP32"
13. Connections between "rb_y1_step" and "ESP32"
14. Connections between "pd_y1_step" and "ESP32"
15. Connections between "q_y1_step" and "ESP32"
16. Connections between "rb_y1_dir" and "ESP32"
17. Connections between "pd_y1_dir" and "ESP32"
18. Connections between "q_y1_dir" and "ESP32"
19. Connections between "drv_y2" and "ESP32"
20. Connections between "motor_y2" and "ESP32"
21. Connections between "rb_y2_step" and "ESP32"
22. Connections between "pd_y2_step" and "ESP32"
23. Connections between "q_y2_step" and "ESP32"
24. Connections between "rb_y2_dir" and "ESP32"
25. Connections between "pd_y2_dir" and "ESP32"
26. Connections between "q_y2_dir" and "ESP32"
27. Connections between "drv_z" and "ESP32"
28. Connections between "motor_z" and "ESP32"
29. Connections between "rb_z_step" and "ESP32"
30. Connections between "pd_z_step" and "ESP32"
31. Connections between "q_z_step" and "ESP32"
32. Connections between "rb_z_dir" and "ESP32"
33. Connections between "pd_z_dir" and "ESP32"
34. Connections between "q_z_dir" and "ESP32"
Deploy the firmware
#include <Arduino.h>
const uint8_t stepPins[]={4,6,8,10};
const uint8_t dirPins[]={5,7,9,11};
bool armed=false, moving=false, invertY2=false, pulseHigh=false;
uint8_t mask=0;
uint16_t remaining=0;
uint32_t nextEdge=0, lastCommand=0;
void stop(){for(auto p:stepPins) digitalWrite(p,LOW);moving=false;pulseHigh=false;remaining=0;}
void help(){Serial.println("ARM: allow one bounded jog; X+/X-/Y+/Y-/Z+/Z-: 100 pulses at 100Hz; STOP or !: stop pulses; DISARM; Y2INV: toggle Y2 direction (uncoupled motors only); HELP. No G-code, no homing, no limits. USB 115200. Each jog requires ARM.");}
void command(String s){s.trim();s.toUpperCase();lastCommand=millis();
if(s=="STOP"||s=="DISARM"){stop();armed=false;Serial.println("Stopped pulses; drivers still hold torque.");return;}
if(moving){Serial.println("Busy; STOP to abort.");return;}
if(s=="HELP"){help();return;}
if(s=="ARM"){armed=true;Serial.println("Armed for ONE jog, 10 second expiry. Uncouple motors first.");return;}
if(s=="Y2INV"){invertY2=!invertY2;armed=false;Serial.printf("Y2 invert=%d\n",invertY2);return;}
if(s.length()!=2||(s[1]!='+'&&s[1]!='-')){Serial.println("Unknown command.");return;}
mask=s[0]=='X'?1:s[0]=='Y'?6:s[0]=='Z'?8:0;
if(!mask||!armed){Serial.println("Use ARM first, then X+, X-, Y+, Y-, Z+, Z-.");return;}
armed=false;
for(int i=0;i<4;i++) if(mask&(1<<i))digitalWrite(dirPins[i],(s[1]=='+')^(i==2&&invertY2));
remaining=100; moving=true; pulseHigh=false;nextEdge=micros()+1000;
Serial.println("100-pulse jog starting.");
}
void setup(){for(int i=0;i<4;i++){digitalWrite(stepPins[i],LOW);digitalWrite(dirPins[i],LOW);pinMode(stepPins[i],OUTPUT);pinMode(dirPins[i],OUTPUT);}Serial.begin(115200);help();}
void loop(){static String line;
while(Serial.available()){char c=Serial.read();if(c=='!'){stop();armed=false;line="";Serial.println("Stopped pulses.");}else if(c=='\n'||c=='\r'){if(line.length()){command(line);line="";}}else if(line.length()<32)line+=c;else{line="";stop();armed=false;}}
if(armed&&millis()-lastCommand>10000)armed=false;
uint32_t now=micros();
if(moving&&(int32_t)(now-nextEdge)>=0){
if(!pulseHigh){for(int i=0;i<4;i++)if(mask&(1<<i))digitalWrite(stepPins[i],HIGH);pulseHigh=true;nextEdge=micros()+100;}
else{for(int i=0;i<4;i++)if(mask&(1<<i))digitalWrite(stepPins[i],LOW);pulseHigh=false;if(--remaining==0){stop();Serial.println("Jog done; disarmed.");}else nextEdge=micros()+9900;}
}
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