RS485 To Wireless Converter API setup

Hardware
1

Hello,

I ordered a RS-485 TO WIRELESS CONVERTER (PR55-34M) recently and I’d like to use the API to read the data from RS485 directly with a linux machine.

I have one Smart Vibration Sensor Gen4 up and running. RS485 Converter is connected to a FTDI 485 to USB cable, then plugged into a linux machine. The linux machine can recognize the FTDI cable as ttyUSB0. However, when i tried to send a command to the 485 converter, i got no response. Here is my code

#!/usr/bin/env python3
"""
Send Read PAN ID command to NCD device
"""

import serial
import time

# Command to send
command = bytes([
    0x7E, 0x00, 0x13, 0x10, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0xFF, 0xFF, 0xFF, 0xFE, 0x00,
    0x00, 0xF7, 0x19, 0x00, 0x00, 0x00, 0xE4
])

# Open serial port
ser = serial.Serial('/dev/ttyUSB0', 115200, timeout=3)

# Send command
print(f"Sending: {command.hex(' ').upper()}")
ser.write(command)
print("Command sent!")

# Wait for response
time.sleep(10)

# Read response
if ser.in_waiting > 0:
    response = ser.read(ser.in_waiting)
    print(f"Response: {response.hex(' ').upper()}")
else:
    print("No response")

ser.close()

Do you guys have any code examples to get the API working for this device?

Thanks!
Xudong

2

Just wrote another script to do some more testing. Run the following code to listen to any output from 485 port

code:

#!/usr/bin/env python3
"""
RS-485 Serial Data Listener
"""

import serial
import sys
from datetime import datetime

def print_data(data):
    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S.%f")[:-3]
    hex_str = ' '.join([f'{b:02X}' for b in data])

    print(f"[{timestamp}] Received {len(data)} bytes:")
    print(f"  HEX:   {hex_str}")
    print()

def main():
    # Serial port configuration
    PORT = '/dev/ttyUSB0'
    BAUDRATE = 9600
    BYTESIZE = serial.EIGHTBITS
    PARITY = serial.PARITY_NONE
    STOPBITS = serial.STOPBITS_ONE
    TIMEOUT = 3

    print(f"RS-485 Listener Starting...")
    print(f"Port: {PORT}")
    print(f"Baudrate: {BAUDRATE}")
    print(f"Config: {BYTESIZE}-{PARITY}-{STOPBITS}")
    print("-" * 50)

    try:
        # Open serial port
        ser = serial.Serial(
            port=PORT,
            baudrate=BAUDRATE,
            bytesize=BYTESIZE,
            parity=PARITY,
            stopbits=STOPBITS,
            timeout=TIMEOUT
        )

        print(f"Listening on {PORT}... (Press Ctrl+C to stop)\n")

        # Continuous reading loop
        while True:
            if ser.in_waiting > 0:
                # Read available data
                data = ser.read(ser.in_waiting)
                print_data(data)

    except serial.SerialException as e:
        print(f"Serial port error: {e}", file=sys.stderr)
        print("\nTroubleshooting tips:")
        print("1. Check if the device is connected: ls -l /dev/ttyUSB*")
        print("2. Check permissions: sudo chmod 666 /dev/ttyUSB0")
        print("3. Add user to dialout group: sudo usermod -a -G dialout $USER")
        return 1

    except KeyboardInterrupt:
        print("\nStopping listener...")

    except Exception as e:
        print(f"Unexpected error: {e}", file=sys.stderr)
        return 1

    finally:
        if 'ser' in locals() and ser.is_open:
            ser.close()
            print("Serial port closed.")

    return 0

if __name__ == "__main__":
    sys.exit(main())

Every time i pressed the “R” button, i got the following respons…

RS-485 Listener Starting...
Port: /dev/ttyUSB0
Baudrate: 9600
Config: 8-N-1
--------------------------------------------------
Listening on /dev/ttyUSB0... (Press Ctrl+C to stop)

[2025-10-27 14:30:23.858] Received 8 bytes:
  HEX:   01 03 00 00 00 01 84 0A

Is there any way i can send command directly to this device 485 device without using Node-red?

3

Hi @xqin For this specific application, you will need the PR55-34_AutoEncoder version. You can select this specific version during the purchasing process. You can fill out an RMA request here: Log In ‹ NCD.io — WordPress to switch your device for the correct version.

Thanks,
Eduardo M

4

Thanks! We’ll fill in the RMA as soon as possible.

Best,
xqin