bazub

while 1:
        a=ser.readline()
        pos=[]
        k=0
        STR=[]
        for i in range (0,len(a)):
            if a[i]==',':
                pos.append(i)
                k=k+1
        for i in range(1,k):

bazub

ser = serial.Serial(
        port='COM3',
        baudrate=38400,
        parity=serial.PARITY_NONE,
        stopbits=serial.STOPBITS_ONE,
        bytesize=serial.EIGHTBITS
    )
    ser.close()
    ser.open()