DELTA RS485 UNOnext Indoor Air Quality Monitor Instructions

June 3, 2024
Delta

DELTA RS485 UNOnext Indoor Air Quality Monitor Instructions

RS485

Following the documents: UNOnext quick start guide and UNOnext Modbus RTU the Building Management
System (BMS) system retrieves the UNOnext data via RS485 interface. If there is any trouble, please check the items below to verify the environment and device settings in the RS485 bus. All referred documents can be found at https://isdweb.deltaww.com/resources.

Environment Settings

  1. Check for correct power from the 9-24V DC input or adapter is correct.
    If the power supply is normal and the UNOnext hardware is normal, the power led is on. If the power supply is normal but the power led is not on, please send UNOnext back for repair.

  2. Check that A2 (+) and B2 (-) are properly connected to Modbus RTU client.

  3.  Check the cable specifications.
    It is recommended to use a 22AWG/24AWG multi-core shielded twisted pair cable or above to achieve the best performance for UNOnext.

  4. Check that the signal and power wire are in the same conduit or not. It is recommended to separate the signal and power wire into separate conduit. Or use the individual power supply for UNOnext. Please refer the following suggested RS485 wire specs:

Twisted Pair Cable

  • 22-24AWG twisted pair, shielded jacketed communication cable.
  • Characteristic impedance of 100-120 ohms.
  • Capacitance of 17 pF/ft conductor-to-conductor or less. 18AWG cable does not meeting this specification.
  • Braided or aluminum foil shield.
  • Velocity of propagation of 66% or higher.

Device Settings

  1. Check the Modbus RTU slave address settings.
    The Modbus RTU slave address is set by DIP switch from [2] to [5] in the back of UNOnext. The DIP definition corresponding to the slave address is shown as below table.

  2. Check the UART settings.
    The UART settings for UNOnext as:
    Baud: 9600 by default, also supports 38400, 57600, 115200 modified by Modbus RTU protocol. (See UNOnext Modbus RTU)
    Data-bit: 8
    Parity: None
    Stop-bit: 1

  3. If the UNOnext daisy-chained for longer distances, please pull up the DIP switch [1] to enable Modbus terminal resister to try.

  4. Try a factory reset.

If the problem is still not solved after checking and modifying the above device settings, please try to restore\ the factory settings.
METHOD: After booting, press the filter reset key three times duration one second to execute factory reset. After factory reset, all settings will be cleaned.

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References

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