Electronics

In our previous example LinuxCNC: How to find current position using Python we showed how to use stat.actual_position to get the current position in machine coordinates using LinuxCNC’s Python API.

#!/usr/bin/env python2.7
import linuxcnc

stat = linuxcnc.stat()
stat.poll()
x,y,z,a,b,c,u,v,w = stat.actual_position

# NOTE: Ignore ABCUVW since not used for my machine
# Subtract G5x offset
xo,yo,zo,ao,bo,co,uo,vo,wo = stat.g5x_offset

x -= xo
y -= yo
z -= zo

# Subtract tool offset
xo,yo,zo,ao,bo,co,uo,vo,wo = stat.tool_offset

x -= xo
y -= yo
z -= zo

# Print offset coordinates
print(x,y,z)

As shown in our previous example LinuxCNC: How to find current position using Python you can get an

These are the attributes of the object returned by linuxcnc.stat() for LinuxCNC 2.7:

acceleration
active_queue
actual_position
adaptive_feed_enabled
ain
angular_units
aout
axes
axis
axis_mask
block_delete
call_level
command
current_line
current_vel
cycle_time
debug
delay_left
din
distance_to_go
dout
dtg
echo_serial_number
enabled
estop
exec_state
feed_hold_enabled
feed_override_enabled
feedrate
file
flood
g5x_index
g5x_offset
g92_offset
gcodes
homed
id
inpos
input_timeout
interp_state
interpreter_errcode
joint_actual_position
joint_position
kinematics_type
limit
linear_units
lube
lube_level
max_acceleration
max_velocity
mcodes
mist
motion_line
motion_mode
motion_type
optional_stop
paused
pocket_prepped
poll
position
probe_tripped
probe_val
probed_position
probing
program_units
queue
queue_full
queued_mdi_commands
rapidrate
read_line
rotation_xy
settings
spindle_brake
spindle_direction
spindle_enabled
spindle_increasing
spindle_override_enabled
spindle_speed
spindlerate
state
task_mode
task_paused
task_state
tool_in_spindle
tool_offset
tool_table
velocity

You can find those out using

#!/usr/bin/env python2.7
import linuxcnc

stat = linuxcnc.stat()
stat.poll()
for entry in dir(stat):
    print(entry)

This will show the position in machine coordinates such as

#!/usr/bin/env python2.7
import linuxcnc

stat = linuxcnc.stat()
stat.poll()
print(stat.actual_position)

Example output:

(7.4023762662053105, 26.443582149595567, 297.289833343029, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0)

Place this file in e.g. linuxcnc/configs/myCNC/custom-mcode/M100

#!/usr/bin/env python2.7
# M100: write timestamp, parameters and gcode filename to linuxcnc/logM100.txt
import sys
import linuxcnc
from datetime import datetime
dt = datetime.now()

stat = linuxcnc.stat() # create a connection to the status channel
stat.poll()

with open("/home/cnc/linuxcnc/logM100.txt", "a") as outfile:
    outfile.write("{} | Args={} | Path={}\n".format(dt.isoformat(), ", ".join(sys.argv[1:]), stat.file))

and make executable using

chmod a+x ./linuxcnc/configs/myCNC/custom-mcodes/M100

Also see our post on how to just read the position especially if you don’t care about the CSV logging: LinuxCNC: How to find current position using Python

This script will log the position to CSV approximately every millisecond. The position will be logged in machine coordinates.

#!/usr/bin/env python2.7
import linuxcnc
import datetime
import time

stat = linuxcnc.stat()

with open("position-log.csv", "w") as outfile:
    while True:
       dt = datetime.datetime.now()
       stat.poll()
       x,y,z,a,b,c,u,v,w = stat.actual_position
       outfile.write("{},{:.4f},{:.4f},{:.4f}\n".format(dt.isoformat(), x, y, z))
       time.sleep(0.001)

with open("/home/cnc/linuxcnc/configs/myCNC/linuxcnc.var") as infile:
    lines = infile.readlines()
    splitted = [line.strip().partition("\t") for line in lines]
    linuxCNCVar = {int(splitResult[0]): float(splitResult[-1]) for splitResult in splitted}

Example output for linuxCNCVar:

{5161: 0.0,
 5162: 0.0,
 5163: 0.0,
 5164: 0.0,
 5165: 0.0,
 5166: 0.0,
 5167: 0.0,
 5168: 0.0,
 5169: 0.0,
 5181: 0.0,
 5182: 0.0,
 5183: 0.0,
 5184: 0.0,
 5185: 0.0,
 5186: 0.0,
 5187: 0.0,
 5188: 0.0,
 5189: 0.0,
 5210: 0.0,
 5211: 0.0,
 5212: 0.0,
 5213: 0.0,
 5214: 0.0,
 5215: 0.0,
 5216: 0.0,
 5217: 0.0,
 5218: 0.0,
 5219: 0.0,
 5220: 1.0,
 5221: 7.40119,
 5222: 13.549249,
 5223: 298.476583,
 5224: 0.0,
 5225: 0.0,
 5226: 0.0,
 5227: 0.0,
 5228: 0.0,
 5229: 0.0,
 5230: 0.0,
 5241: 36.868548,
 5242: 141.752329,
 5243: 207.563262,
 5244: 0.0,
 5245: 0.0,
 5246: 0.0,
 5247: 0.0,
 5248: 0.0,
 5249: 0.0,
 5250: 0.0,
 5261: 36.868548,
 5262: 145.029329,
 5263: 207.563262,
 5264: 0.0,
 5265: 0.0,
 5266: 0.0,
 5267: 0.0,
 5268: 0.0,
 5269: 0.0,
 5270: 0.0,
 5281: 36.89201,
 5282: 144.834924,
 5283: 207.935105,
 5284: 0.0,
 5285: 0.0,
 5286: 0.0,
 5287: 0.0,
 5288: 0.0,
 5289: 0.0,
 5290: 0.0,
 5301: 0.0,
 5302: 0.0,
 5303: 0.0,
 5304: 0.0,
 5305: 0.0,
 5306: 0.0,
 5307: 0.0,
 5308: 0.0,
 5309: 0.0,
 5310: 0.0,
 5321: 0.0,
 5322: 0.0,
 5323: 0.0,
 5324: 0.0,
 5325: 0.0,
 5326: 0.0,
 5327: 0.0,
 5328: 0.0,
 5329: 0.0,
 5330: 0.0,
 5341: 0.0,
 5342: 0.0,
 5343: 0.0,
 5344: 0.0,
 5345: 0.0,
 5346: 0.0,
 5347: 0.0,
 5348: 0.0,
 5349: 0.0,
 5350: 0.0,
 5361: 0.0,
 5362: 0.0,
 5363: 0.0,
 5364: 0.0,
 5365: 0.0,
 5366: 0.0,
 5367: 0.0,
 5368: 0.0,
 5369: 0.0,
 5370: 0.0,
 5381: 0.0,
 5382: 0.0,
 5383: 0.0,
 5384: 0.0,
 5385: 0.0,
 5386: 0.0,
 5387: 0.0,
 5388: 0.0,
 5389: 0.0,
 5390: 0.0}