Normally the WattNode® meter Modbus address is specified using the DIP switches on the front of the meter (see the manual for details). The address can be factory configured by ordering the meter with Option AD=xxx where xxx is the desired Modbus address. This supports any Modbus address from 1 to 247 (0 is the broadcast address and 248..255 are reserved).

It is also possible to field configure the Modbus address using the Address register, but you must establish communications before you can change the Address register.

Overriding Option AD

If you have a WattNode Modbus meter with Option AD and you need to change the address, it can be done, but there are a few considerations:

  • When ordered with Option AD, the address is factory programmed as the default value for the Address register.
  • The address DIP switches are ignored because of the factory programmed Address register. The DIP switches will all be set to 0 (OFF).
  • Whenever the DIP switches are all set to 0 (OFF), the WattNode will reset all communication configuration settings—Address, BaudRate, ParityMode, and ModbusMode—to the factory default values every ten seconds. So if you want to change any of these, you will need to change the DIP switches to something other than zero first.

There are two ways to change the address on a WattNode Modbus meter ordered with Option AD:

Using the DIP Switches

  1. Set the DIP switches to the desired address.
  2. Write 0 to the Address (1652) register (this is necessary to override the factory programmed address and have the DIP switches take effect).
  3. Write 1234 to the ApplyComConfig (1651) register to apply the new address.

Using the Address Register

  1. Set the DIP switches to any non-zero address so the meter won’t reset the address to the factory programmed value.
  2. Write the desired address to the Address (1652) register.
  3. Write 1234 to the ApplyComConfig (1651) register to apply the new address.

Notes

All WattNode Modbus meters can have their communication settings restored to factory shipped values by setting all DIP switch positions to “0” for ten seconds. The factory default settings will include any specified options.

If you cannot communicate with a meter that was ordered with option AD, we recommend setting all the DIP switches to zero, then try to communicate with the meter at the address specified by Option AD. If other options were also specified, such as baud rate, parity, etc., be sure to match those as well. If the Option AD address may conflict with another device on the bus, isolate the meter from other devices on the bus until you can establish communication and change the address.