An error at the connection with URM08-SEN0246 using Python

Hi,

I connect URM08-Ultrasonic Distance Sensor (link is here: https://www.dfrobot.com/product-1913.html) to Jetson Orin Nano via FTDI’s USB-RS485 converter (link is here: https://www.mouser.jp/ProductDetail/FTDI/USB-RS485-WE-1800-BT?qs=nE%2FgAoToukEKIIQwhDYwQw%3D%3D). So I’m using Pyserial instead Arduino IDE, but generally succeed to link the sensor and the computer.

 However, sometimes the sensor stop sending data, sending only empty data and it never response even I send detection command to it after this error happen in the same session. For example, ordinary the sensor responses like:

b'U\xaa\x11\x02\x02\x00Xl'  //print(ser.leadline())

88  cm                                        //print((ser.leadline()[5]>>8 | ser.leadline[6]), “ cm”)

b'U\xaa\x11\x02\x02\x00Wk'

87  cm

b'U\xaa\x11\x02\x02\x00Wk'

87  cm

…

However, when the error happens, sensor returns no data like:

b''

1

b''

2

b''

3

…

This numbers are just error counts, counts for empty data response, so please ignore them. I wonder what is a cause of this error. Could you know why this error happens?

Thanks