Coolometer data gathering script

coolometer.py

import serial

probe_z = 45
x_range = [-40, 40]
y_range = [-30, 60]
step = 2

def do_command(port,s):                     # send command and look for ok reply
    while True:
        port.write(s)
        if s == "M114\n":
            port.readline()
        line = port.readline()
        if line[:2] == 'ok': 
            break
        print "Retry:", s, line.strip()

def read_meter(meter):                      # read power from coolometer
    do_command(meter,'s')
    return int(meter.readline().split()[5][:-3])

def wait_for_move(printer):                 # wait for printer move to finish
    do_command(printer,"M400\n")            # wait for motion buffer empty
    do_command(printer,"M114\n")            # will only reply when processed
   

printer = serial.Serial('/dev/ttyUSB0', 250000, timeout = None)
do_command(printer,"M107\n")                # fan off
do_command(printer,"G28 Z0\n")              # home z

meter = serial.Serial('/dev/ttyUSB1', 9600, timeout = 5)
print "init: ", meter.readline().strip()    # coolometer sends a reading when reset
do_command(meter,'z')                       # set zero power level
do_command(printer,"M201 X1000 Y100\n")     # very low Y acceleration to avoid coolometer slipping
do_command(printer,"G28 X0 Y0\n")           # home x and y
do_command(printer,"G1 X0 Y0 F12000\n")     # goto centre
do_command(printer,"G1 Z%d\n" % probe_z)    # move nozzle to just above the probe
wait_for_move(printer)                      # wait for moves to finish
do_command(printer,"M106\n")                # turn the fan on

f = open("fanmap.dat","w")                  #write file for GNUplot
for y in range(y_range[0], y_range[1] + 1, step):
    for x in range(x_range[0], x_range[1] + 1, step):
        do_command(printer,"G1 X%d Y%d F12000\n" % (x,y))
        wait_for_move(printer)
        if x == x_range[0]:                 # extra delay at start of line for temperature to stabilise after quick trip under the fan
            read_meter(meter)
        power = read_meter(meter)
        print x, y, power
        print >> f, x, y, power
    print >> f
f.close()

do_command(printer,"M107\n")                #fan off
do_command(printer,"M18\n")                 #motors off
printer.close()
meter.close()