I'm attempting to put together a cnc plotter/milling machine, and being on a rather tight budget, am trying to use what I've got on hand.
I've modified a carriage from an OKI dot matrix printer, and am trying to use the servo motor with it's encoder along with the original mechanicals for the carriage.
I have already gotten GRBL working on one of my Uno clones, and would like to put this on a mini clone to run the DC servo motor for the X axis.
I've found someone who has done this on his 3D printer, and for him it seems to work quite well.
He has his code and some explanations on GitHub GitHub - misan/dcservo: Position control of DC motors
In trying to compile the sketch, I get several error messages, right at the end of compiling. That is to say it appears to be compiling, then exits with several errors.
In looking at the build folder I.E. user>>>>\buildxxxx.tmp...... I don't see a .cpp.h file, so it definitely isn't finishing the compile.
Here is the .ino file:
/* This one is not using any PinChangeInterrupt library */
/*
This program uses an Arduino for a closed-loop control of a DC-motor.
Motor motion is detected by a quadrature encoder.
Two inputs named STEP and DIR allow changing the target position.
Serial port prints current position and target position every second.
Serial input can be used to feed a new location for the servo (no CR LF).
Pins used:
Digital inputs 2 & 8 are connected to the two encoder signals (AB).
Digital input 3 is the STEP input.
Analog input 0 is the DIR input.
Digital outputs 9 & 10 control the PWM outputs for the motor (I am using half L298 here).
Please note PID gains kp, ki, kd need to be tuned to each different setup.
*/
#include <EEPROM.h>
#include <PID_v1.h>
#define encoder0PinA 2 // PD2;
#define encoder0PinB 8 // PC0;
#define M1 9
#define M2 10 // motor's PWM outputs
byte pos[1000]; int p=0;
double kp=3,ki=0,kd=0.0;
double input=0, output=0, setpoint=0;
PID myPID(&input, &output, &setpoint,kp,ki,kd, DIRECT);
volatile long encoder0Pos = 0;
boolean auto1=false, auto2=false,counting=false;
long previousMillis = 0; // will store last time LED was updated
long target1=0; // destination location at any moment
//for motor control ramps 1.4
bool newStep = false;
bool oldStep = false;
bool dir = false;
byte skip=0;
// Install Pin change interrupt for a pin, can be called multiple times
void pciSetup(byte pin)
{
*digitalPinToPCMSK(pin) |= bit (digitalPinToPCMSKbit(pin)); // enable pin
PCIFR |= bit (digitalPinToPCICRbit(pin)); // clear any outstanding interrupt
PCICR |= bit (digitalPinToPCICRbit(pin)); // enable interrupt for the group
}
void setup() {
pinMode(encoder0PinA, INPUT);
pinMode(encoder0PinB, INPUT);
pciSetup(encoder0PinB);
attachInterrupt(0, encoderInt, CHANGE); // encoder pin on interrupt 0 - pin 2
attachInterrupt(1, countStep , RISING); // step input on interrupt 1 - pin 3
TCCR1B = TCCR1B & 0b11111000 | 1; // set 31Kh PWM
Serial.begin (115200);
help();
recoverPIDfromEEPROM();
//Setup the pid
myPID.SetMode(AUTOMATIC);
myPID.SetSampleTime(1);
myPID.SetOutputLimits(-255,255);
}
void loop(){
input = encoder0Pos;
setpoint=target1;
myPID.Compute();
if(Serial.available()) process_line(); // it may induce a glitch to move motion, so use it sparingly
pwmOut(output);
if(auto1) if(millis() % 3000 == 0) target1=random(2000); // that was for self test with no input from main controller
if(auto2) if(millis() % 1000 == 0) printPos();
//if(counting && abs(input-target1)<15) counting=false;
if(counting && (skip++ % 5)==0 ) {pos[p]=encoder0Pos; if(p<999) p++; else counting=false;}
}
void pwmOut(int out) {
if(out<0) { analogWrite(M1,0); analogWrite(M2,abs(out)); }
else { analogWrite(M2,0); analogWrite(M1,abs(out)); }
}
const int QEM [16] = {0,-1,1,2,1,0,2,-1,-1,2,0,1,2,1,-1,0}; // Quadrature Encoder Matrix
static unsigned char New, Old;
ISR (PCINT0_vect) { // handle pin change interrupt for D8
Old = New;
New = (PINB & 1 )+ ((PIND & 4) >> 1); //
encoder0Pos+= QEM [Old * 4 + New];
}
void encoderInt() { // handle pin change interrupt for D2
Old = New;
New = (PINB & 1 )+ ((PIND & 4) >> 1); //
encoder0Pos+= QEM [Old * 4 + New];
}
void countStep(){ if (PINC&B0000001) target1--;else target1++; } // pin A0 represents direction
void process_line() {
char cmd = Serial.read();
if(cmd>'Z') cmd-=32;
switch(cmd) {
case 'P': kp=Serial.parseFloat(); myPID.SetTunings(kp,ki,kd); break;
case 'D': kd=Serial.parseFloat(); myPID.SetTunings(kp,ki,kd); break;
case 'I': ki=Serial.parseFloat(); myPID.SetTunings(kp,ki,kd); break;
case '?': printPos(); break;
case 'X': target1=Serial.parseInt(); p=0; counting=true; for(int i=0; i<300; i++) pos[i]=0; break;
case 'T': auto1 = !auto1; break;
case 'A': auto2 = !auto2; break;
case 'Q': Serial.print("P="); Serial.print(kp); Serial.print(" I="); Serial.print(ki); Serial.print(" D="); Serial.println(kd); break;
case 'H': help(); break;
case 'W': writetoEEPROM(); break;
case 'K': eedump(); break;
case 'R': recoverPIDfromEEPROM() ; break;
case 'S': for(int i=0; i<p; i++) Serial.println(pos[i]); break;
}
while(Serial.read()!=10); // dump extra characters till LF is seen (you can use CRLF or just LF)
}
void printPos() {
Serial.print(F("Position=")); Serial.print(encoder0Pos); Serial.print(F(" PID_output=")); Serial.print(output); Serial.print(F(" Target=")); Serial.println(setpoint);
}
void help() {
Serial.println(F("\nPID DC motor controller and stepper interface emulator"));
Serial.println(F("by misan"));
Serial.println(F("Available serial commands: (lines end with CRLF or LF)"));
Serial.println(F("P123.34 sets proportional term to 123.34"));
Serial.println(F("I123.34 sets integral term to 123.34"));
Serial.println(F("D123.34 sets derivative term to 123.34"));
Serial.println(F("? prints out current encoder, output and setpoint values"));
Serial.println(F("X123 sets the target destination for the motor to 123 encoder pulses"));
Serial.println(F("T will start a sequence of random destinations (between 0 and 2000) every 3 seconds. T again will disable that"));
Serial.println(F("Q will print out the current values of P, I and D parameters"));
Serial.println(F("W will store current values of P, I and D parameters into EEPROM"));
Serial.println(F("H will print this help message again"));
Serial.println(F("A will toggle on/off showing regulator status every second\n"));
}
void writetoEEPROM() { // keep PID set values in EEPROM so they are kept when arduino goes off
eeput(kp,0);
eeput(ki,4);
eeput(kd,8);
double cks=0;
for(int i=0; i<12; i++) cks+=EEPROM.read(i);
eeput(cks,12);
Serial.println("\nPID values stored to EEPROM");
//Serial.println(cks);
}
void recoverPIDfromEEPROM() {
double cks=0;
double cksEE;
for(int i=0; i<12; i++) cks+=EEPROM.read(i);
cksEE=eeget(12);
//Serial.println(cks);
if(cks==cksEE) {
Serial.println(F("*** Found PID values on EEPROM"));
kp=eeget(0);
ki=eeget(4);
kd=eeget(8);
myPID.SetTunings(kp,ki,kd);
}
else Serial.println(F("*** Bad checksum"));
}
void eeput(double value, int dir) { // Snow Leopard keeps me grounded to 1.0.6 Arduino, so I have to do this :-(
char * addr = (char * ) &value;
for(int i=dir; i<dir+4; i++) EEPROM.write(i,addr[i-dir]);
}
double eeget(int dir) { // Snow Leopard keeps me grounded to 1.0.6 Arduino, so I have to do this :-(
double value;
char * addr = (char * ) &value;
for(int i=dir; i<dir+4; i++) addr[i-dir]=EEPROM.read(i);
return value;
}
void eedump() {
for(int i=0; i<16; i++) { Serial.print(EEPROM.read(i),HEX); Serial.print(" "); }Serial.println();
}
I'll post the error codes in a reply, as this doesn't want to post with them in.