DYMO usb scale reading (multiple scales)

read_scales.py

import sys
import usb.core
VENDOR_ID = 0x0922
PRODUCT_ID = 0x8003


# find USB devices
devices = list(usb.core.find(find_all=True, idVendor=VENDOR_ID,
                       idProduct=PRODUCT_ID))
                       

# loop through devices, printing vendor and product ids in decimal and hex

print("len=",len(devices))
masses=[]
sum=0

for device in devices:
  cfg=device
  #sys.stdout.write('Decimal VendorID=' + str(cfg.idVendor) + ' & ProductID=' +     str(cfg.idProduct) + '\n')
  #sys.stdout.write('Hexadecimal VendorID=' + hex(cfg.idVendor) + ' & ProductID=' + hex(cfg.idProduct) + '\n\n')
  #print("device=",device)
  device.set_configuration()
  # first endpoint
  endpoint = device[0][(0,0)][0]
  # read a data packet
  attempts = 10
  data = None
  while data is None and attempts > 0:
      try:
          data = device.read(endpoint.bEndpointAddress,
                           endpoint.wMaxPacketSize)
      except usb.core.USBError as e:
          data = None
          if e.args == ('Operation timed out',):
              attempts -= 1
              continue

  #print (data)
  mass = data[5]*256+data[4]
  sum += mass
  masses.append(mass)
  #print("mass=",mass)

print("masses=",masses)
print("sum=",sum)