code:

 
#include <AccelStepper.h>

AccelStepper s1(1,22,23);
AccelStepper s2(1,24,25);
AccelStepper s3(1,26,27);
AccelStepper s4(1,28,29);
AccelStepper s5(1,30,31);
AccelStepper s6(1,32,33);
AccelStepper s7(1,34,35);
AccelStepper s8(1,36,37);
AccelStepper steppers[]={s1,s2,s3,s4,s5,s6,s7,s8};
int endstops[]={52,53,44,45,46,47,48,49};
int numaxes =4;
int channel=0;
int route;
long routevalue;
long count=1;
long lastt=0;
long dist;

void setup() {
Serial.begin(115200);
  for (int x=0; x< numaxes;x++){
  steppers[x].setMaxSpeed(500);
  steppers[x].setAcceleration(100);
  pinMode(endstops[x],INPUT);
  }
}

void loop() {
  parseinputcomplex();
  movesteppers();
  framerate();
}

void movesteppers(){
    for (int x=0; x< numaxes ;x++){
    dist=steppers[x].distanceToGo();
    if(dist<0&&digitalRead(endstops[x])==1){
      steppers[x].setCurrentPosition(0);
      steppers[x].moveTo(0);
    }
    if (dist!=0){
    steppers[x].run();
    }
  }
}

void parseinput(){// targets an axis to a set location. Syntax is
[channel value]. Can stack multiple commands.
    while (Serial.available() > 0) {
    channel = Serial.parseInt();
    routevalue = Serial.parseInt();
    steppers[channel].moveTo(routevalue);
    Serial.print(channel);
    Serial.print(" ");
    if (Serial.read() == '\n') {
      Serial.println("go");
    }
  }
}

void parseinputcomplex(){// allows for a broader range of commands
than parseinput. Syntax is [channel command value] ie [0 1 200].
Commands can stack.
    while (Serial.available() > 0) {
    channel = Serial.parseInt();
    route= Serial.parseInt();
    routevalue = Serial.parseInt();

    if (route==0){//Set target position
    steppers[channel].moveTo(routevalue);
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(" Target Position ");
    Serial.println(routevalue);
    }

    if (route==1){//move by
    steppers[channel].moveTo(routevalue+steppers[channel].targetPosition());
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(" Move By ");
    Serial.println(routevalue);
    }

    if (route==2){//set max speed
    steppers[channel].setMaxSpeed(routevalue);
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(" Max speed ");
    Serial.println(routevalue);
    }

    if (route==3){//set  accelleration
    steppers[channel].setAcceleration(routevalue);
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(" Accelleration ");
    Serial.println(routevalue);
    }

    if (route==4){//set current location
    steppers[channel].setCurrentPosition(routevalue);
    Serial.print("Channel ");
    Serial.print(channel);
    Serial.print(" Current position set to ");
    Serial.println(routevalue);
    }

    if (route==5){//report status. Channel and value not used. Use
dummy value (such as 0). All distance units in steps.
      for(int n=0;n<numaxes;n++){
      Serial.print("Chn ");
      Serial.print(n);
      Serial.print(" Targ. Pos ");
      Serial.print(steppers[n].targetPosition());
      Serial.print(", Cur. Pos ");
      Serial.print(steppers[n].currentPosition());
      Serial.print(", Current Spd ");
      Serial.print(steppers[n].speed());
      Serial.print(", Current Max Spd ");
      Serial.println(steppers[n].maxSpeed());
      }
    }

    if (Serial.read() == '\n') {
      Serial.println("go");
    }
  }
}

void framerate(){
    if(count%50000==0){
    Serial.print(1000*count/(millis()-lastt));
    Serial.println(" Cycles per second");
    lastt=millis();
    count=0;
  }
   count=count+1;
}