Automatic tool changer for Linuxcnc with Arduino UNO

ATCduino ( Automatic tool changer arduino ) is tool changer for 8 stations tools on a geneva wheel controling a pololu dc geared motor with encoder (64 ppr x 131 reduction) the motor controled in closed position PID loop based on (misan pid dc servo).

The ATC can work as standalone or in conjuction with linuxcnc, commands to the ATC are sent through serial port. When connected to Linuxcnc a remap M6 is essential to make it work

through your serial connection to ATCduino send these commands followed by new line:

• Homing : Send Mxxxx where xxxx is the distance in forward direction after returning to home sensor.
• Move : Send Xxxxx where xxxx is the distance in forward direction, return a message (See message).
• Piston Forward : Send O (not zero).
• Piston Backward: Send J.
• Set PID P : Send Pxxx where xxx the value of proportional gain accept float point.
• Set PID I : Send Ixxx where xxx the value of Integral gain accept float point.
• Set PID D : Send Dxxx where xxx the value of Dervative gain accept float point.
• Get PID settings : Send Q, will return a message with settings (kp,ki,kd)
• Save PID settings to eeprom : Send W.
• Recover PID settings : Send R.
• Clear PIDsettings : Send K.
• Get position: Send '?' without quotes, return position.
• Get "How am I" : Send '!" witout quotes, return "ATC" this is used in communication with linuxcnc.
• Get "Firmware version" : Send F, return firmware version.
• Get Home sensor state : Send T return 1 = On or 0=off.
• Reset position : Send B, no return message will be recieved but you can read postion sending '?'.

After sending a move command ATCduino will send back a message including the following:

• IN position 1 = position reached , or 0 = still moving.
• Current position.
• Target position.
• Enabled 1 = can run, 0 = blocked,(can the motor run connected to piston retract signal).

the message is comma separated (inposition, Currentposition , Target position, Enabled ).

Due to serial communication some glitches may occur if no command is sent, to overcome 
this glitches a move command must  be always sent to arduino, to make sure no glitchs will happen.

Copy the following files to your config Directory:

• ATCduino.hal
• ATCduino.py
• ATCduino_gui.hal
• ATCduinoui.py
• ATCduino.ui
• postgui_list.hal
• nc_subroutines (Whole Directory).
• python (Whole Directory).

In you ini file add the following lines (make sure the first 5 lines are in [RS274NGC] section, other lines doesn't matter where to pu them

SUBROUTINE_PATH = nc_subroutines:python:../../nc_files/remap_lib/common_nc_subs:macros
LOG_LEVEL = 9
FEATURES = 30
ON_ABORT_COMMAND = O <on_abort> call
REMAP=M6   modalgroup=6  prolog=change_prolog   ngc=rack_change  epilog=change_epilog

[CHANGE_POSITION]
X = 10
Y = 100
Z = -50

[ATCPINS]
# This is the pin number which connected to motion.digital-out-xx
##outputs

PISTON = 0
HOME = 1
#Change this pin number to match machine's  spindle digital output number .
LOCK = 2
SAVEEPROM = 3

#inputs

ENABLE = 0
INPOSITION = 1

#Analog output
CMDSTATION = 0

[DWELL]
LOCK_TIME = 1.5
MYSTERY = 2
NEW_TOOL = 1.0
POST_UNLOCK = 0.5
PISTON_TIME_OUT = 2
TURNING_TIME_OUT = 25
[STATIONS]
S1 = 0
S2 = 8384
S3 = 16768
S4 = 25152
S5 = 33536
S6 = 41920
S7 = 50304
S8 = 58688

[HOMING]
OFFSET = 4000

[PID]
ATCP = 37
ATCI = 32
ATCD = 0.57

refer to gmoccapy.ini to see how they are arranged. note we must add ATCduino.hal to HAL section in the ini file

HALFILE = ATCduino.hal
# Single file that is executed after the GUI has started.
POSTGUI_HALFILE = postgui_list.hal

also note instead of calling postgui.hal we replaced it with postgui_list.hal to add extra post gui hal files.

Importatnt note for tool prepare-tool prepared and and tool change - tool changed loop signals must be available in you hal file refer to core_sim.hal

As a role of thumb lin linuxcnc when adding a new component always start linuxcnc from a terminal

cd /home/USERNAME/linuxcnc/configs/YOUR_CONFIG
then
linuxcnc YOUR_CONFIG.ini

it's easier to debug any problems during startup, you must see during startup a message similar to the following:

Found ATC (Auto tool changer) and connecting on port /tty/USB0 

when linuxcnc exit you will see

ATC has been disconnected

after a successful startup you will notice a screen ATC you can edit your settings there also for quick calibration, or you can change them directly in the ini file.

a normal tool change command like

T2M6

will do the following:

1. Tool wheel will turn to corresponding pocket (if changed).
2. Piston will extend to receive the tool.
3. Return loaded tool to it's pocket.
4. Disingage tool from spindle.
5. Safty move away from the tool.
6. Retract piston.
7. Turning to the new requested tool pocket.
8. Extend piston.
9. Move spindle to receive position.
10. Lock tool in spindle.
11. Retract piston.
12. Safty move for spindle, tool is ready. to change order of movement depending on your setup refer to /nc_subroutines/rack_change.ngc for complete usage

Take extra measures when using manual commands, these commands used when a certain movemnt of ATC needed you can do it from 2 places

1. from ATC settings screen.
2. from gcode commands (refer to /nc_subroutines/rack_change.ngc for complete usage)

Turnning wheel
M68 E(analog output) Q(pocket)
(analog output) refer to ini file section [ATCPINS] to know which analog output motion pin is used
example:
'M68 E0 Q3 =  Turn wheel on output 0 to station 3'

Piston moves
1. M64 P(piston digital output) set digital output pin on meaning set piston forward.
2. M65 P(piston digital output) set digital output pin off meaning set piston backward.
(piston digital output) refer to ini file section [ATCPINS] to know which digital output motion pin is used

Homing
Piston moves
1. M64 P(homing digital output) set digital output pin on meaning set piston forward.
(homing digital output) refer to ini file section [ATCPINS] to know which digital output motion pin is used