If an indoor unit is not controlled as part of a retail zone (see attached RTD-20 installation instructions for details on the Retail Zone modes), but instead as stand-alone, i.e. only to be controlled with Modbus or a wired remote controller then the RTD-20 can be set to operate like a RTD-NET interface. In this case the RTD-NET Modbus Holding and Input registers must be used (see attached RTD-NET installation instructions for list of Modbus registers). Note, that in this operation mode VAM units can be controlled, too.
To operate the RTD-20 as a RTD-NET set the RTD-20 to operate as Partition Mode Slave:
DIP switches 1 - 4: ON ON ON OFF.
DIP switches 5 - 8: OFF OFF OFF ON (Modbus network address 1), or OFF OFF ON OFF (Modbus network address 2), or OFF OFF ON ON (Modbus network address 3).
Always start with the lowest Modbus network address.
*Note: In this configuration, after power-up the RTD will start the unit, LED2 will flash to indicate Partition Mode Master not found, and R2 will be energised.
While the RTD-NET has a timeout functionality that can be disabled, it is not possible to disable it when the RTD-20 is used as a RTD-NET replacement.
By writing the value 65535 to the RTD-20 Modbus Holding register 30009, the timeout activation is extended to 65535 seconds. Any write to any Modbus Holding register will reset the timer.
* Note: Timeout functionality cannot be turned off completely. Use your system to reset the timer.
If a wired remote controller is used then configure it as MAIN P1P2 device (see wired remote controller installation instructions).