How to install the RTD-RA

Mounting, Power and S21

Mounting

  • The RTD must either be mounted in a suitable metal enclosure or plastic enclosure with a flammability rating of at least IEC60695-11-10 V-1. Do not install it inside the air-conditioning unit. In all cases access by non-qualified persons must be prevented (the enclosure may not accessible without a tool). The unit can be mounted horizontally or vertically.
  • All cable connections to the device must be adequately secured by suitable strain relief fasteners. Cables supplied with strain relief bands must be fitted in the corresponding cable guide slot with the strain relief band inside of the enclosure.

Power and S21:

  • ONLY 1 indoor units can be wired to a RTD-RA.
    • You may be able to connect several indoor units (of which each has its own RTD-RA) to a Multitype condensing unit. Please contact Daikin Technical Support for further information.
  • The RTD-RA is supplied with a pre-fitted lead for power and communication with the Room Air-conditioner. The lead allows a maximum distance of 950mm from RTD-RA to the connection point in the indoor unit. The lead must be fitted and secured through suitable access points in the air-conditioner and the connector must be inserted into port S21 on the Room Air-conditioner indoor unit control PCB.
    • *Note: We do not offer any extended cables, or extenders for the supplied pre-fitted lead. Therefore, if you require longer leads then please contact Daikin Technical Support for further information on the electrical specs of the cables.
  • The S21 lead enters the RTD-RA through Port D on the enclosure as shown in figure 1 (see attached installation instructions), the lead is supplied pre-fitted to J1 on the RTD-RA PCB. The fitted strain relief band on the cable must be located on the inside of the enclosure. *Note: For information about the S21 pin descriptions please contact Daikin Technical Support.

Inputs S1 and S2

  • Cable connections to J6 inputs S1 and S2 must be 0.5 to 0.75 mm2 multi-stranded screened twisted pair. The screen must be earthed at one end only. The maximum distance from the RTD to the input source is 200m.

For further information, please contact Daikin Technical Support.

 

RS485 

  • RS485 Cables must use stranded 24awg shielded or unshielded twisted pair to Cat3, Cat4 or Cat5 specification. Use a twisted pair for connections DB,DA and an extra core for connection GND. Install RS485 cable as shown in figure 3 of the RTD-RA installation instructions. For further detail see page 6 of the installation instructions (RS485 Network Installation) and our article RS485 network requirements.
  • The RS485 Network lead must be connected to terminals J5 on the RTD-RA PCB and must be fitted through Port B on the enclosure as shown in figure 1 of the attached RTD-RA installation instructions. The PCB mounted strain-relief must be used to secure the network cable. Cables must have a maximum outside diameter of 5mm. 

DIP switches

The RTD-RA offers several operation modes which can be set using the DIP switches. See the article 'What is the RTD-10 used for?' and the RTD-RA installation instructions for details on DIP switch settings. 

 

Hardwired Inputs (S1 and S2)

Dependent on the operation mode of the RTD-RA the various functions can be set using the hardwired inputs S1 and S2.

Please see the RTD-RA installation instructions for further information.

 

Modbus

The RTD-RA supports the Standard RTU Modbus protocol. Please follow this link for RTD baud rate and parity settings. For information regarding Modbus communication please have a look at this article: Using Modbus with our interfaces.

Set the RTD-RA to Modbus Slave Operation (see page 10 of RTD-RA installation instructions) for Modbus control/monitoring.

All available registers and parameters are listed in the RTD-RA installation instructions. Additional paramaters supported by the indoor unit cannot be controlled with the RTD-RA if not listed in the RTD-RA installation instructions.

 

Remote Controller 

The standard infrared remote controller can be used to control the indoor unit unless the operation mode to which the RTD-RA is set (with the DIP switches and inputs) limits or locks the controller's functions.

Note the following:

  • If the RTD-RA is set to Stand-Alone mode some functions of the remote controller may be locked (see pages 9 and 10 of the RTD-RA installation instructions).
  • When the RTD-RA is operated as Modbus slave the remote controller can be used simultaneously. Note that some or all functions of the remote controller can be locked using Modbus (see pages 11 and 12 of the RTD-RA installation instructions).
  • When in Clone Mode the remote controller is disabled.
  • When in RTD-10 Duty/Standby mode the remote controller is locked. For further information please see the article RTD-10 Duty/Standby operation mode.
  • When in RTD-20 User Control Zone mode the remote controller's functions are restricted. Please see the RTD-RA and RTD-20 installation instructions for further information.

 

Status LEDs

The RTD LEDs signal various statuses during start-up, as well as during operation. For explanation of the LED signals please see page 7 and respective figures in the RTD-RA Installation instructions.

 

Fault Signals

A Fault is signalled with LED2 (see page 7 and respective figure in the RTD-RA Installation instructions). The exact fault code can be read either on the remote controller display or via Modbus (see the article RTD Fault Codes).

Please note following cases:

  • RTD-RA Clone mode: In this operation mode the RTD-RA does not send a fault signal to the interface it is cloning. To read the Fault either read the remote controller dosplay or, if Modbus is used, add a RTD-DSX to the Modbus Network and read the Fault from the respective Fault Register of the RTD-RA. 
  • Duty/Standby mode: In this configuration the RTD-10 Duty/Standby master will monitor temperature and fault conditions from the RTD-RA in the same way it monitors RTD-10, so faults from the RTD-RA will be reported at the master correctly.

Testing

Testing can be performed via Modbus using our free software ModTool (see this article: ModTool Communication with our Products).

Note that testing only is possible with an indoor unit connected to the RTD-RA.