Igntion vision 8.1

I have this:
writeBytes([\x01])
If I write a byte in hexadecimal I should receive the same ,but why the response is 127.
Can anyone tell me, please?

Sorry, you’ll need to provide a little more detail about what you’re doing.

This is where I am writing the byte

And here I am reading and getting the 127

Tip: please copy the code from your screen and post it using the </> code formatting button. That way we can copy and paste and edit it in our answers.

One problem you have is stopBis. It should be stopBits.

I am using an interface USB to SR485
The ports, I am using a converter



import time 
with system.serial.port(
port = "COM3",
bitrate = system.serial.BIT.RATE_19200,
databits = system.serial.DATA.BITS_8,
handshake = system.HANDSHAKE_NONE,
hardwareFlowControl = False,
parity = system.serial.PARITY_MARK,
stopBits = system.serial.STOP_BITS_1) as portOutAddress:

portOutAddress.writeBytes([\x01])
time.sleep(0.1)




with system.serial.port(
port="COM9",
bitrate = system.serial.BIT.RATE_19200,
databits = system.serial.DATA.BITS_8,
handshake = system.HANDSHAKE_NONE,
hardwareFlowControl = False,
parity= system.serial.PARITY_NONE,
stopbits = system.serial.STOP_BITS_1) as port:
L= port.readBytes(1, 10000)
print L

Your erroneous transcription and screenshots also use bitrate instead of bitRate for the parameter.

See system.serial.port - Ignition User Manual 8.1 - Ignition Documentation for the parameter names.

I think you may have a configuration or hardware issue. I don’t have any real hardware to test with, but it seems fine with a pair of virtual ports:

import time

with system.serial.port(
	port = "/tmp/vserial33",
	bitRate = system.serial.BIT_RATE_38400) as p1:
	
    p1.writeBytes([\x01])

time.sleep(0.1)

with system.serial.port(
	port = "/tmp/vserial44",
	bitRate = system.serial.BIT_RATE_38400) as p2:
	
    print p2.readBytes(1, 1000)

Output:

>>> 
array('b', [1])
>>> 

Let me check the hardware, I changed bitrate for bitRate, thanks