To assign an address to the tags you wish to transmit/receive through MODBUS communication do the following:

1. Configure the PLC as Master or Slave according to your needs.

2. Add a new operation

To add an array to be read/write via MODBUS, select a tag within an array.
When you select the tag, you will see a square bracket symbol “ [ “ To send the array, just delete the bracket and press Enter.

3. After linking the tag, add the address in the Address column.
4. When you add the next operand,  it will automatically assign the next free address.