EMCO Compact 5 cnc Turret with dc motor and no feedback

I start with a pyvcp panel...
Drive fwd 1 station button calls in section in my comp
Set tool 1 button calls m61q1

Then i add buttons tool1 tool2.... tool6 to call m6 t1....t6

If i hit drive fwd 1 station it rotates exact 1 station fwd. goes then backward and reduce pwm to get it locked against the pawl.

Now i check temperature ever 15 minutes of driver and dc motor.

Next step is calculating the distance from actual tool position to taeget tool position.. like from tool 1 to tool 6... or from tool 6 to tool 3... handling the rollover would be interesting... we will see in the next days.

If this done is the last step the movement... with the calculated distance on position to go forward i can multiplie with the forwardtime from position to position.. the locking part is not so sensitive.

So we will see... toolchanger without feedback... very oldschool... complete openloop.

Sam was working on this a few years ago.
Look at this.


It might help.

I got it working.

No feedback needed.
3 pins are used..

Forward
Backward
Pwm pulse

L298n cheap modul.

I clean up the component and then i make a small video und can share the code.

I use a 8 position toolchsnger from my emco 220 where i unmount the lightbarrier pcb.

How it works:

Start linuxcnc..
Then 1 time make movement over a button of the toolchanger.
Then look which tool is in position.
Then set toolnumber over buttons.

After this all is done over timing.
No motor noise!
No overheating!
No issues!

Rollover is handled.
The biggest problem was to find the correct timings and speeds.

The reason for the issue is that the dc motor has a planetary gear and the wormgear has small play.

You can setup:
How many toolslots you have
Time from slot to slot
Backward time
Backward locking time

Pwm for forward
Pwm for backward
Pwm for locking against the pawl

Advantage:
If you hit emergency off the toolchanger stops and resets

You can add reference signal to tool1
You can drive toolchanger from slot 2 slot over buttons.

You have pins where you csn see if you have rollover and the slots it must travel.

Its complete openloop and can setup over a hal or halpkns