[tessen]

Hi, i´m building a cnc lathe, i have no problem with mechanical part but i´m a begginer with Kflop and C programming, ok, i´ll try to explain that i have and what i would like achieve

the plate with the 8 tools turn with a servomotor (currently config in kflop like A axis, set it like 1mm is one tool jump), i can lock/unlock the plate base with a pneumatic cilinder, commanded by a electric valve driven by kflop board (IO20) through external relay, i leave a video of the mechanical assembly
CNC TURRET 8 POSITION TOOL CHANGER FOR A CNC LATHE - YouTube
the secuence can be like this:

- set the tool
- unlock the turret plate (IO20 on)
- wait time
- turn the A axis (1mm = 1 tool, G0 A8 is the tool 8))
- wait time
- lock the turret plate (IO20 off)

note: the second wait time it´s not the same for all tool change, to change tool 1 to the tool 2 it´s shorter than change from tool 1 to the tool 8

and i would like to do this:
- make the tool change using "T" and "M06" commanded in the Gcode program, the tool plate should turn by the shortest path

and in other side, i´ll would like to use and external control, in this control i have 8 buttons (each button it´s wired to one input to kflop) ok, when i press one tool button, the turret unlock (IO20) the tool plate, turn (A axis) to the commanded tool and lock again, if i press one tool button more than 4sg, the turret don´t turn but set this tool like the working tool, and if i pulse more than one button--> error, or don´t move

regards
P.D: when it works, I promise to upload a video

[TomKerekes]

Hi tessen,

Are you planning to use mach3 or KMotionCNC?

Which axis channel controls the Turret?

How many counts or steps per tool?

Regards

[tessen]

Hi Tom, thank for your help
from i have tried kmotioncnc i don't want to hear to speak about mach3
the turret axis is the channel 2, to change one tool i have to send 4250 pulses (34000pulses/rev)

best regards

[TomKerekes]

Hi tessen,

On power up how will you be able to determine where the turret is? Will you do some sort of Home sequence?

Regards

[tessen]

Hi Tom
currently i don't have any homing sequence, i have to set it manually, for this reason i would like to set the tool position from the external control

[TomKerekes]

Hi tessen,

Oh so on power up the Operator will need to check what tool position it is currently at. If he/she sees that it is at tool position 7 then he/she will hold down button #7 for 4 seconds. Is that correct?

Regards

[tessen]

Hi Tom
yes, that's right

regards

[TomKerekes]

Hi tessen,

Here is some code. You forgot to specify some things like how/where the 8 buttons would be connected. You may have to change some defines.

It turned out a bit more complex because it is written as a state machine. A state machine approach allows a single Thread of execution to keep track of what it is doing and go off and do something else and then come back to what it was doing.

Actually there are two state machines ServiceToolChange and ServiceToolButtons. The first does your little unclamp, wait, move turret, clamp, wait, sequence. The second monitors the buttons to see if one is pushed or released and for how long and then either initializes the position, starts a tool change, or does nothing.

I've included a main forever loop to call the two state machines so you can test running as a separate Thread. But after it is all working you can add the calls to your Init program loop.

Here is the code:

#include "KMotionDef.h"

// Services Tool Changer using non-blocking State Machine approach
// The Service routines maintain their state so they can always return
// immediately and later resume from their previous state.

// T O O L   C H A N G E R   S E Q U E N C E
//
// define state that the tool changer may be in
enum {T_IDLE,T_START,T_WAIT_UNCLAMP,T_WAIT_MOVE,T_WAIT_CLAMP};

#define TOOL_VAR 9        	// Tool changer desired new tool Var
#define TOOL_STATE_VAR 8  	// Tool changer state is saved globally in this Var
#define LAST_TOOL_VAR 7   	// Tool changer Last tool position is saved globally in this Var
#define TOOL_CLAMP_BIT 20 	// IO bit number to clamp turret
#define TOOL_DIST 4250.0	// Steps/counts to move turret to next tool
#define CLAMP_TIME 1.5    	// seconds to wait for the clamp/unclamp
#define TURRET_AXIS 2     	// axis channel for the turret motor

int *ChangerState 	= &persist.UserData[TOOL_STATE_VAR];
int *Tool     		= &persist.UserData[TOOL_VAR];
int *LastTool 		= &persist.UserData[LAST_TOOL_VAR];

double ToolTime;

// Services Tool Change Sequence
void ServiceToolChange(void)
{
    switch (*ChangerState)
    {
    case T_IDLE:
        {
            break;
        }
    case T_START:
        {
            if (*LastTool==0)
            {
                printf("Error Turret Position Never defined\n");
                *ChangerState = T_IDLE;  // go idle
            }
            else if (*Tool > 8 || *Tool < 1)
            {
                printf("Invalid Tool Number %d\n",*Tool);
                *ChangerState = T_IDLE;  // go idle
            }
            else
            {
                printf("Tool Change Unclamp\n");
                ClearBit(TOOL_CLAMP_BIT);  // Release Clamp
                ToolTime = Time_sec() + CLAMP_TIME;  // wait until this time
                *ChangerState = T_WAIT_UNCLAMP;
            }
            break;
        }
    case T_WAIT_UNCLAMP:
        {
            if (Time_sec() > ToolTime)
            {
                // time to move.  Compute distance

                int delta = *Tool - *LastTool;  // how far to move 
                if (delta>4)  delta-=8;		// optimize direction
                if (delta<-4) delta+=8;

                printf("Turret Moved From %d to %d, delta = %d\n", *LastTool,*Tool,delta);
                *LastTool = 0;  // set as undefined while moving
                MoveRel(TURRET_AXIS,delta*TOOL_DIST);

                *ChangerState = T_WAIT_MOVE;
            }
            break;
        }
    case T_WAIT_MOVE:
        {
            // check if disabled
            if (!chan[TURRET_AXIS].Enable)
            {
                *ChangerState = T_IDLE;
            }
            else if (CheckDone(TURRET_AXIS))
            {
                printf("Tool Change Clamp\n");
                SetBit(TOOL_CLAMP_BIT);  // Clamp
                ToolTime = Time_sec() + CLAMP_TIME;  // wait until this time
                *ChangerState = T_WAIT_CLAMP;
            }
            break;
        }
    case T_WAIT_CLAMP:
        {
            // if clamped go idle
            if (Time_sec() > ToolTime)
            {
                printf("Tool Change Complete\n");
                *LastTool = *Tool;  // remember where we are
                *ChangerState = T_IDLE;
            }
            break;
        }
    }
}

// E X T E R N A L   T O O L   B U T T O N   M A N A G E M E N T 
//
// define states that the tool button service may be in
enum {T_IDLE,T_ONE_BUTTON_PUSHED};

double ToolButtonTime;
int ButtonState = T_IDLE;
int LastButton;

#define FIRST_TOOL_BUTTON 36
#define NUM_TOOL_BUTTONS 8

#define LONGPUSH 4.0  	// Push button this long to force tool number
#define SHORTPUSH 1.0  	// Push button this long to do tool change

// returns button number 0-N if one single button pushed
// otherwise returns -1 if no buttons pushed
// or -2 if more than one button pushed

int CheckForOneButtonPushed(void)
{
    int i,b,n=0;

    for (i=0; i<NUM_TOOL_BUTTONS; i++)
    {
        if (ReadBit(FIRST_TOOL_BUTTON+i))
        {
            b=i; // rememeber last one
            n++; // remember how many
        }
    }
    if (n==1) return b; 	// one pushed, return which one
    if (n==0) return -1; 	// none pushed, return -1
    return -2; 				// more than one, return -2
}

// Services Some Operator buttons to perform two functions
// A short duration push of a single button will cause a tool change
// A long duration push of a single button will set the current turret
// position as that tool number
void ServiceToolButtons(void)
{
    int NewButton=CheckForOneButtonPushed();
    double T=Time_sec();

    switch (ButtonState)
    {
    case T_IDLE:
        {
            // Single button pushed?
            if (NewButton >= 0)
            {
                LastButton=NewButton;
                ToolButtonTime=T;
                ButtonState = T_ONE_BUTTON_PUSHED;
            }
            break;
        }
    case T_ONE_BUTTON_PUSHED:
        {
            // same one still pushed?
            if (NewButton != LastButton)
            {
                // no, check for more than one pushed
                if (NewButton==-2)
                {
                    // more than one, do nothing and start over
                }
                // check how long it had been pushed
                else if (T > ToolButtonTime + LONGPUSH)
                {
                    *LastTool = LastButton+1;  // set tool number
                    printf("Turret Set as Tool %d\n",*LastTool);
                }
                else if (T > ToolButtonTime + SHORTPUSH)
                {
                    // short push, initiate a ToolChange if
                    // Tool Changer is idle
                    if (*ChangerState == T_IDLE)
                    {
                        *Tool = LastButton+1;  // set new tool to load
                        *ChangerState = T_START;  // Go!
                        printf("Tool %d Change Initiated\n",*Tool);
                    }					
                }
                ButtonState = T_IDLE;  // go back to idle state
            }
            break;
        }
    }
}

// Loop servicing things
main()
{
    for (;;)  // loop forever
    {
        WaitNextTimeSlice();
        ServiceToolChange();
        ServiceToolButtons();
    }
}

Here is a program that you can assign to your M6 to initiate a Tool change from GCode.

#include "KMotionDef.h"

// Assumes a Tool Changer State Machine is running in a forever loop
// (which is necessary to allow external buttons to change tools)

#define TOOL_STATE_VAR 8  	// Tool changer state is saved globally in this Var
#define TOOL_VAR 9        	// Tool changer desired new tool Var
// define state that the tool changer may be in
enum {T_IDLE,T_START,T_WAIT_UNCLAMP,T_WAIT_MOVE,T_WAIT_CLAMP};

main()
{
    int *ChangerState    = &persist.UserData[TOOL_STATE_VAR];
    int Tool = persist.UserData[TOOL_VAR];  // value stored is an integer 

    if (*ChangerState == T_IDLE)
    {
        *ChangerState = T_START;  // Go!
        printf("Tool %d Change Initiated\n",Tool);

        // wait till finished
        while (*ChangerState != T_IDLE)
            WaitNextTimeSlice();
    }
    else
    {
        printf("Error Tool Changer not idle");
    }					
}

There are a number of debug messages included. So if it doesn't work check the Console Screen for what happens.

Regards

[tessen]

Hi Tom
i try to run your program, but not works yet, i don't know that i´m doing wrong
this is my config

M6 (Extecute prog)-->Thread 2 -->VAR 0 --> C file=ToolM6TrigService.c

in thread 1 i have running my init file and i can move all axis, to test the program i launch the ServiceToolChange.c in the thread 3 but nothing happens when i try to change the tools through command line

TOOLS (all buttons are Normally Closed, conected to +3.3v)
T1 --> IO23
T2 --> IO24
T3 --> IO25
T4 --> IO31
T5 --> IO32
T6 --> IO33
T7 --> IO45
T8 --> IO44

best regards and thanks for your time

[TomKerekes]

Hi tessen

The M6 must be configured to pass the Tool Number in the Var that the C program is looking for it. This is defined in the C program as:

#define TOOL_VAR 9 // Tool changer desired new tool Var

Using Thread #2 is ok. But you may want to change to Execute Prog/Wait so that the GCode will wait until the tool change finishes.

Couldn't you see where to change the Button IO numbers? Change:

#define FIRST_TOOL_BUTTON 36

to

#define FIRST_TOOL_BUTTON 23

If your Buttons are all negative logic (go low when pushed - check the Digital I screen). Then change:

if (ReadBit(FIRST_TOOL_BUTTON+i))

to

if (!ReadBit(FIRST_TOOL_BUTTON+i))


In the C Language the "!" symbol is the "NOT" operator.

HTH
Regards

[tessen]

Hi Tom!
the toolchanger running, the video i had promised

[TomKerekes]

Nice! I like the tool change dance.
Thanks