Description

Before deployment, you can click Fetch in ToolBox to check if Milesight LoRaWAN controller(UC50x series, UC1152, UC11-N1) can get RS485 terminal device data correctly.

This article will describe how to trouble shooting when you fail to fetch the RS485 device data from ToolBox.


 

Solution

Part 1: RS485 Device Check

  1. The RS485 device must support Modbus RTU protocol.
  2. Check if the RS485 device has powered on and started up. If you use Milesight Controller (UC50x series or UC11-N1) to power the device, note that the controller only powers on the device when it’s ready to upload data to network server according to reporting interval. It’s sugguested to power on the RS485 device via external power supply during PoC procedure.
  3. Download Modbus Poll or other software to simulate as Modbus master (client) and connect RS485 device to PC to check if the device can be read by the software. During test, please set the read quantity as 1 or 2.


 


Part 2: Controller Check

  1. Check if basic serial port setting is correct.
  2. Ensure the Modbus channel setting is saved before clicking Fetch button.
  3. Ensure the Modbus setting is correct.

    Example: send Modbus read command 01030001840A (Slave ID=1, type = holding register, address=0, quantity=1), ToolBox setting is as below:

    Besides, you can use the Modbus Poll setting to confirm ToolBox setting.

    Note: for some protocol document, it will show address as below list. If 40001 does not work, please type address as 1 in ToolBox.

    Data Type
    		Address Range
    Coil
    		1 - 9999
    Discrete Input
    		10001 - 19999
    Input Register
    		30001 - 39999
    Holding Register
    		40001 - 49999

  4. Increase the response time and re-try time. Some RS485 device respone time is slow, which may cause timeout. Besides, you can also shorten the response time of RS485 device.


 

Part 3: Cable Check and Others

  1. Check if RS485 A and B wirings do not reverse.
  2. Change another connecting cables with small length difference.
  3. Connect a 120 Ωresistor in parallel between A and B cable. For UC50x series device or UC1152, you can change the DIP switch on the board to add the resistor. For details about DIP switch please refer to UC50x User Guide or contact Milesight support about it.


If you need any help for deeper trouble-shooting, feel free to contact Milesight Technical Support.