Posts made by padeja

The firmware update from 4.6 to 5.56 made the trick and the /dev/ttyNS0 now works as expected, therefore it can be used as Modbus master as intended.

nipi@M203-sn21:~$ sudo /opt/unipi/tools/fwspi --auto
Board on /dev/unipispi firmware=4.6  hardware=0.1 (B-1000) (spi 6MHz)
New firmware 5.56 for device id=0 fw=4.6

REBOOTING...
Board on /dev/unipispi firmware=4.6  hardware=8.1 (E-16Di_U-14Ro) (spi 6MHz)
New firmware 5.56 for device id=1 fw=4.6

REBOOTING...

thanks @Martin-Kudláček for your help!

@padeja said in Modbus RTU devices connection:

Hi @Martin-Kudláček,

thank you for you reply and the important information that the serial device ttyNS* has nothing to do with Evok.
I was actually trying just before installing Evok simply swap the USB-RS485 converter device to the Neuron serial interface in my script, but it didn't work as such. I was testing the connection also from CLI using mbpoll but with the same result - no communication / answer.

when I look at USB vs Neron serial device configurations using setserial, I receive following:

pi@M203-sn21:~ $ setserial -ag /dev/ttyUSB0
/dev/ttyUSB0, Line 0, UART: unknown, Port: 0x0000, IRQ: 0
        Baud_base: 24000000, close_delay: 0, divisor: 0
        closing_wait: infinite
        Flags: spd_normal

pi@M203-sn21:~ $ setserial -ag /dev/ttyNS0
/dev/ttyNS0, Line 0, UART: undefined, Port: 0x0000, IRQ: 201
        Baud_base: 600, close_delay: 50, divisor: 0
        closing_wait: 3000
        Flags: spd_normal low_latency

I would say at least UART type and Baud_base should be configured. Did I miss a step in Neuron configuration?

Hi @Martin-Kudláček,

thank you for you reply and the important information that the serial device ttyNS* has nothing to do with Evok.
I was actually trying just before installing Evok simply swap the USB-RS485 converter device to the Neuron serial interface in my script, but it didn't work as such. I was testing the connection also from CLI using mbpoll but with the same result - no communication / answer.

Hi all,
I am trying to connect RS485 devices to Neuron M203 over modbus rtu protocol.

I have started from raspbian kernel and then installed kernel modules from unipi repository: https://repo.unipi.technology/debian/

ending up with kernel:
Linux M203-sn21 5.10.17-v7+

then I can see the serial device in: "/dev/extcomm/0/0" ("/dev/ttyNS0")

However, when I switch in my minimal python script from existing serial interface connected to USB (USB<->RS458 converter) to the ttyNS0 device I get timeout error (No communication/answer). The TX light on Neutron blinks once when I send the request.

#!/usr/bin/env python3

import minimalmodbus

#instrument = minimalmodbus.Instrument('/dev/ttyUSB0', 1, minimalmodbus.MODE_RTU)
instrument = minimalmodbus.Instrument('/dev/ttyNS0', 1, minimalmodbus.MODE_RTU)
instrument.serial.baudrate=9600
instrument.serial.bytesize = 8
instrument.serial.parity = minimalmodbus.serial.PARITY_EVEN

PV = instrument.read_register(4096, 1)
print("PV: ", PV, "C")

in Evok I have added the setting for the UART Port:

Could you please advise me how to setup Neuron as a master for RS-485 communication?

Thanks,
Jaroslav