Hello,
the config file is utterly wrong. If you don't use any extension, you need to comment out all the lines of the [EXTENSION_1] block, not just the [EXTENSION_1] line. The syntax of this config file is based on the INI file. That means the active lines of the config where assigned to the [NEURON_1] block, thus resulting in unexpectable behaviour.
;[EXTENSION_1]
global_id = 2 ; Mandatory, REQUIRED TO BE UNIQUE
device_name = xM103 ; Mandatory
modbus_uart_port = /dev/extcomm/0/0 ; Mandatory
;neuron_uart_circuit = 1_01 ; Optional, allows associating extensions wi$
;allow_register_access = True ; Optional, False default, is mandatory with third-p$
;address = 1 ; Optional, 1 default
;scan_frequency = 10 ; Optional, 10 default
;scan_enabled = True ; Optional, True default
; Note that the following settings will be inherited by other devices sharing the same port, i.e. /d$
baud_rate = 38400 ; Optional, NEEDS UNIPI IMAGE TO WOR$
parity = N ; Optional, NEEDS UNIPI IMAG$
stop_bits = 1 ; Optional, NEEDS UNIPI IMAGE TO WOR$