Laser Electronics

Laser Cutter Electronics

File:Laser-control board.pdf

File:Laser-motor driver.pdf

Laser control board pinout

Left Header: (Top to Bottom)

• GND (Shield)
• SW_1 (Yellow)
• SW_2 ( Green)
• SW_4 (Blue)
• SW_8 (Lt Purple)
• Disable (Lt Brown)
• ...

Top Header: (left to right)

• Output to LEDs
• PWM output to laser tube (2 pins - black, red)

Bottom Header: (Left to right)

• Laser EN (Black)
• ...
• (I/O to parallel port here)

Right Header: (Top to bottom)

• ...
• (Power Input & output to stepper driver)

Laser Power controller board pinout

Long header:

• yellow = switch input
• blue = parallel input
• green = output to PIC (where switches used to go)

Top header:

• Pin 1 (Orange wire) LASER_EN
• Pin 3,4 - (Purple) Mode Switch
• Pin 5 - Ground
• Pin 6 - 5V

Code

When we replaced the motor controllers back in 2016; we moved the step generation logic off the PIC, and replaced it with a single "MOTOR_EN" output instead.

The original code changes have not been found, so the following is assumed but unvalidated.

/*
 * Laser Engraver Controller - ver. 1.1a
 *
 * Written by: Andrew Kilpatrick
 * Copyright: 2009, 2016
 *
 * Runs on PIC16F877A
 *
 * Functional Description:
 *  - support for connection to emc2 or similar host-driven CNC software
 *  - parallel port or other type of bit-bang connection to PC
 *  - E-stop and system run control support (amp enable, charge pump, etc.)
 *  - controls laser PWM control
 *
 * Hardware I/O:
 *  - RA0    - laser power bit 0        - input - active high
 *  - RA1    - laser power bit 1        - input - active high
 *  - RA2    - laser power bit 2        - input - active high
 *  - RA3    - laser power bit 3        - input - active high
 *  - RA4    - laser defeat            - input - active high
 *
 *  - RB0    - E stop loop            - input - 0 = run, 1 = stop
 *  - RB3    - motor_enable            - output
 *  - RB4    - laser activate        - input - 0 = off, 1 = on
 *
 *  - RC0    - amp enable LED        - output - 0 = off, 1 = on
 *  - RC1    - laser LED            - output - 0 = off, 1 = on
 *  - RC2    - laser PWM            - output - 0 = off, 1 = on
 *
 *  - RE0    - E stop output            - output - 0 = stop, 1 = run
 *  - RE1    - amp enable input        - input - 0 = disable, 1 = enable
 *  - RE2    - charge pump input        - input - high pulses to charge
 *
 */
#include <system.h>

#pragma CLOCK_FREQ 20000000

#pragma DATA 0x2007, _CP_OFF & _DEBUG_OFF & _CPD_OFF & _LVP_OFF & _BODEN_ON & _HS_OSC & _WDT_ON & _PWRTE_ON

// inputs
#define LASER_POWER_1_IN porta.0
#define LASER_POWER_2_IN porta.1
#define LASER_POWER_4_IN porta.2
#define LASER_POWER_8_IN porta.3
#define LASER_DEFEAT_IN porta.4
#define E_STOP_IN portb.0
#define MOTOR_EN portb.3
#define LASER_IN portb.4
#define AMP_ENABLE_IN porte.1
#define CHARGE_PUMP_IN porte.2

// outputs
#define AMP_ENABLE_LED portc.0
#define LASER_ON_LED portc.1
#define E_STOP_OUT porte.0

// laser setting
#define LASER_TICKLE 0x01

// run state machine
#define STATE_IDLE 1
#define STATE_RUN 2
#define STATE_E_STOP 3
unsigned char run_state;

// globals
unsigned char run;                // 1 = normal, 0 = stopped
unsigned char charge_pump;        // 0 = stopped, >0 = run
unsigned char old_ch_pump;
unsigned char laser_init;        // 1 = laser initialized, 0 = not initialized
unsigned char laser_power;        // laser power level
unsigned char laser_on;            // 1 = laser on, 0 = laser off
unsigned char flash;            // temp flasher variable

// function prototypes
void step_laser(void);

// main loop
void main() {
    // set up IO
    porta = 0x00;
    trisa = 0xff;  // inputs
    adcon1 = 0x06;  // all digital pins
   
    portb = 0x00;
    trisb = 0xF7;  // inputs except for MOTOR_EN
    option_reg.NOT_RBPU = 0;  // weak pullups
   
    portc = 0x00;
    trisc = 0x00;  // outputs
    AMP_ENABLE_LED = 0;
    LASER_ON_LED = 0;
    ccpr1l = 0x00;
    ccp1con = 0x0c;  // PWM mode
    t2con = 0x05;  // prescaler 4, timer on
   
    trise.PSPMODE = 0;  // no data port
   
    porte = 0x00;
    trise &= 0xfe;  // RE0 = output, RE1-2 = input
    E_STOP_OUT = 1;  // no E stop

    t1con = 0x21;  // 1:4 prescaler, internal clock, timer on

    // reset temp vars
    run = 0;
    laser_init = 0;
    laser_on = 0;
    flash = 0;
    run_state = STATE_IDLE;
    charge_pump = 0;
    old_ch_pump = 0;

    // bootup light dance
    AMP_ENABLE_LED = 0;
    LASER_ON_LED = 1;
    delay_ms(250);
    delay_ms(250);
    AMP_ENABLE_LED = 1;
    LASER_ON_LED = 0;
    delay_ms(250);
    delay_ms(250);
    AMP_ENABLE_LED = 0;

    // loop
    while(1) {
        clear_wdt();
       
        // do stuff every 50ms
        if(pir1.TMR1IF) {
            pir1.TMR1IF = 0;
           
            // charge pump
            if(charge_pump) charge_pump --;
           
            // EMERGENCY STOP!
            if(E_STOP_IN) {           
                run_state = STATE_E_STOP;               
                E_STOP_OUT = 0;
               
                // turn off the laser
                ccpr1l = 0x00;  // power level to 0
                ccp1con &= 0xcf;  // power level to 0
                laser_power = 0;
                laser_on = 0;
                LASER_ON_LED = 0;
           
                // turn off motors
                MOTOR_EN=0;
                portc &= 0x0f;


                // LED flashing
                flash = (flash + 1) & 0x07;
                if(flash & 0x04) {
                    AMP_ENABLE_LED = 1;
                }
                else {
                    AMP_ENABLE_LED = 0;
                }
            }
            // E STOP cleared - enter idle state
            if(run_state == STATE_E_STOP && !E_STOP_IN) {
                run_state = STATE_IDLE;
                AMP_ENABLE_LED = 0;
                E_STOP_OUT = 1;
            }
            // amplifier enabled - enter run state
            if(run_state == STATE_IDLE && AMP_ENABLE_IN && charge_pump > 0x7f) {
                run_state = STATE_RUN;
                AMP_ENABLE_LED = 1;
                ccpr1l = LASER_TICKLE;  // make tickle puses for the laser
                ccp1con |= 0x30;  // PWM mode
                                //enable motors:
                                MOTOR_EN=1;

            }
            // amplifier disabled - enter idle state
            if(run_state == STATE_RUN && (!AMP_ENABLE_IN || charge_pump < 0x80)) {
                run_state = STATE_IDLE;
                AMP_ENABLE_LED = 0;

                // turn off the laser
                ccpr1l = 0x00;  // power level to 0
                ccp1con &= 0xcf;  // power level to 0
                laser_power = 0;
                laser_on = 0;
                LASER_ON_LED = 0;
           
                // turn off motors
                MOTOR_EN=0;
                portc &= 0x0f;
            }
           
            // handle laser power adjustments in run state
            if(run_state == STATE_RUN) {
                // laser power adjust
                if(LASER_DEFEAT_IN) {
                    // force laser into tickle
                    ccpr1l = LASER_TICKLE;
                    laser_power = 0;
                    LASER_ON_LED = 0;
                }
                else {
                    laser_power = (porta & 0x0f) << 4;
                    // if laser is on, change power immediately
                    if(laser_on) {
                        ccpr1l = laser_power;
                        LASER_ON_LED = 1;
                    }
                }
            }           
        }
       
        // handle charge pump on rising edge
        if(CHARGE_PUMP_IN && !old_ch_pump) {
            if(charge_pump != 0xff) charge_pump ++;
        }
        old_ch_pump = CHARGE_PUMP_IN;
    }
}

Tube

The tube on the laser cutter is a 25W Synrad F48-2S

Manual for that version does not appear online, but here are manuals for newer ones:

• File:Synrad-g48v21.pdf
• File:Synrad-j48v54.pdf
• File:Synrad-48SeriesM v8.2.pdf