Arduino controlled stepper motor for Mill X-axis drive

[nevilletParticipant @nevillet]

Thanks for all your help on this thread.

On Dave’s suggestion I’ve managed to deenergise the motor stopping it dead by using the ENA +/- terminals.

I’ve fed the ENA+ with +5V and to stop the motor, grounding the ENA- terminal.

The next stage in this project is coupling the X lead screw to the motor shaft with a coupling made on the lathe. (I’ll start a new thread..)

[nevilletParticipant @nevillet]

The Arduino is controlling the stepper driver and it works but not quite as I’d want.

At the moment I have a speed control and a push button switch that changes the motor direction.
To stop the motor i’m using the ENABLE+ & ENABLE- terminals on the controler but this is not via the Arduino but rather directly.

What I’d like is to do is have a single 3 position switch (On-Off-On) that controls the direction and the enable functionality.

It would also help if a couple of LED’s were employed to show which position (Forward-Stop-Reverse) the switch was in.

Can anyone suggest how to code this?

(this is the sketch I’m using at the moment)

 

 

int reverseSwitch = 2; // Push button for reverse
int driverPUL = 7; // PUL- pin
int driverDIR = 6; // DIR- pin
int spd = A0; // Potentiometer

// Variables

int pd = 500; // Pulse Delay period
boolean setdir = LOW; // Set Direction

// Interrupt Handler

void revmotor (){

setdir = !setdir;

}

void setup() {

pinMode (driverPUL, OUTPUT);
pinMode (driverDIR, OUTPUT);
attachInterrupt(digitalPinToInterrupt(reverseSwitch), revmotor, FALLING);

}

void loop() {

pd = map((analogRead(spd)),0,1023,2000,50);
digitalWrite(driverDIR,setdir);
digitalWrite(driverPUL,HIGH);
delayMicroseconds(pd);
digitalWrite(driverPUL,LOW);
delayMicroseconds(pd);

}

 

[John HaineParticipant @johnhaine32865]

A simple way to use such a 3 position switch is to connect its common to ground and connect the other two poles each to an input with a pullup enabled.  Then if both inputs are HIGH you disable the drive, or depending on which is LOW drive in one direction or the other.  No need to use interrupts for this.

One thing to watch out for is if you have the feedrate set quite high and suddenly ask the stepper to move it may well stall.  Ideally you program an acceleration ramp and there are standard Arduino libraries to do this – accelstepper is one I recall. I think that it also takes care of all the pulse generation stuff, hopefully without using delay() function.

One of the reasons for using GRBL to generate the pulses is that all the acceleration stuff is already taken care of.

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