code: def _read_weights(self):
          
          weights = []
  
          grams_per_pound = 453.592
  
          # Read from each of the sensors
          for ser in self._serials:
              ser.write('W\r')
              ser.flush()
          time.sleep(0.02)
          for ser in self._serials:
              try:
                  output_str = ser.readline()
                  weight = float(output_str) * grams_per_pound
                  weights.append(weight)
              except:
                  weights.append(0.0)
  
          # Log the output
          log_output = ''
          for w in weights:
              log_output +='{:.2f} '.format(w)
          rospy.loginfo(log_output)
  
          return weights
docs: Reads weights from each of the load cells.