Mounting
The RTD interface can be mounted on DIN rails, or on a surface using screws of up to 5mm diameter.
The RTD-20 is supplied with 4 mounting pillars that can be used to mount the interface within units with compatible mounting holes.
Please contact Daikin Technical Support for further details on mounting a RTD interface inside a Daikin indoor unit, as they as can advise you better on their products.
Power
The RTD requires a 15V to 24VDC power connection (see the power ratings, as well as WARNINGS and CAUTIONS on page 4 of attached installation instructions). Power can be supplied from VRV indoor unit PCB X18A or X35A connection, a Skyair indoor unit PCB X35A connection or VAM PCB X11A connection. If the power supply is taken from the X35A/X18A, limitation of options is possible (example: KRP1C shall not be connected). Please contact Daikin Technical Support for further details on powering the RTD from a unit. A 1m cable and connector is supplied with the RTD.
An external DC power supply can be used as power source, too.
P1P2
Please follow this link for information about P1P2 network requirements. The RTD-20 is wired to the P1P2 network at its P1P2 terminal block.
Please note that RTD-20 acts as a remote controller. As such it sends a specific command to the indoor unit. If you require information on how the indoor unit works when a specific command is recieved (e.g. when in Cooling mode and Return Air temperature is below requested setpoint) then please contact Daikin Technical Support.
Please note the following when several indoor units are wired to one P1P2 network:
- They are assigned a P1P2 network address. The P1P2 address is designated to the units through Daikin's system. Please contact Daikin Technical Support for further information on P1P2 address settings.
- Any command sent from the RTD-20 or wired remote controller (if connected) is broadcast to all of these indoor units on the same P1P2 network, i.e. they behave the same.
Wired remote controller
If the RTD-20 must be set as MAIN P1P2 device then it can operate without an additional wired remote controller, i.e. in this case the remote controller is optional.
- With respect to compatibility of wired remote controllers to our RTD interfaces, please read this article.
Whether the RTD-20 is to operate as MAIN or SUB P1P2 device depends on the operation mode set by the installer (using the DIP switches). Please read the details in the attached installation instructions (pages 6 - 8, and respective operation mode sections).
- The information whether the RTD-20 must be configured as MAIN P1P2 or SUB P1P2 device is given in the header of each operation mode section in the RTD-20 installation instructions.
Please follow this link for information on how to configure a device to MAIN or SUB P1P2 mode.
The remote controller may be locked/unlocked in specific operation modes. For information about locking in retail mode please see the article RTD-20 Retail mode - Remote Controller locking.
Infrared remote controller
When using infrared remote controllers the BRC infra-red receivers must be configured to operate in SUB (S) mode.
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 4 of the RTD-20 installation instructions. For further detail see page 5 of the installation instructions (RS485 Network Installation).
DIP switches
The RTD-20 offers several operation modes which can be set using the DIP switches. See the article 'What is the RTD-20 used for?' and the RTD-20 installation instructions for details on DIP switch settings.
Hardwired Inputs (S1 - S6)
Dependent on the operation mode of the RTD-20 various parameters can be controlled using the hardwired inputs (S1 - S6). If the selected operation mode (using the DIP switches) and your application don't require the use of hardwired inputs then they can be left open.
- If electric resistors (no specific resistors required) are used for control then the resistance values should be within +/-250 ohms of the quoted value. Open circuit is R>200kΩ.
- If several electrical resistance values are wired simultaneously (in parallel) on an Input (e.g. 2.2kOhm, 3.3kOhm, and 4.7kOhm) then the RTD-20 interface will only see the total electric resistance value on its input (Note: total value of parallel electric resistances: 1/Rtotal = 1/R1 + 1/R2 + 1/R3...)
- If Voltage is used for control then Voltage values should be within +/- 0.25V of the quoted value. Open circuit for V<1V.terminal S-S6 do not supply power. If any device (e.g. sensor) wired to the inputs S1 - S6 needs a power source then this has to be implemented 'externally'.
- If the input value is too close to the outer range (+/- 250 Ohms or +/- 0.25 V) of a quoted value the RTD-20 may not react. Therefore, please make sure you're well within the range and test.
- Always close the circuit between a S-input and '0V' of the same terminal block. Note that this applies too when all S-inputs of the same terminal block are used.
- Note that controlling is done 'externally' with your BMS system (Modbus and/or hardwired inputs). How ever the external control is implemented it does not affect the RTD-20 operation, as long as the input values are correct.
Please see the RTD-20 installation instructions for information on parameters controlled with hardwired inputs and the required Voltage/Resistance values.
Modbus
The RTD-20 supports the Standard RTU Modbus protocol over the RS485 network (no other protocol is supported). Please follow this link for RTD baud rate and parity settings.
The RTD-20 can be operated either in Retail Mode or in specific modes for stand-alone operation. If you're unsure which mode you require, please see the article What is the RTD-20 used for?.
When configured to Retail Mode the RTD-20 operates as a stand-alone network with the Primary Primary Shop Floor Zone (Modbus address '0') acting as Modbus master. In this case monitoring via Modbus only is possible using a Modbus gateway. We recommend our Modbus gateway RTD-DSX. For further information on the RTD-DSX see the article RTD-DSX: Our Modbus gateway.
When using the RTD-20 for stand-alone operation (supported modes: VAM, Air curtain, Partition slave, ERQ) then control with the Modbus registers listed in the RTD-20 installation instructions. Further readback registers for monitoring are listed in the RTD-NET installation instructions (Input Registers are read-only).
- Exception: If the RTD-20 is to be used as Partition slave it acts as a RTD-NET. For details please see the article RTD-20: Individually control an indoor unit with Modbus.
Readback registers: Note that when using Modbus the readback registers (Modbus 'input registers') are all listed in the attached RTD-NET installation instructions.
Modbus address: To set the Modbus address please set the DIP switches as shown in figure 6 (page 3) of the RTD-20 installation instructions.
For additional information on using Modbus with the RTD-20 interface please see the article Using Modbus with our interfaces.
Relays
The RTD-20 uses dry (VFC: Volt-Free Contacts) relay contacts which do not have a required connection polarity. Note that the relays do not supply power. They only open/close the circuit.
Please, when loading the relays do not exceed the power ratings specified on page 4 in the installation instructions (attached below).
The relays' default status is normally open and they close when there is respective signal.
Status LEDs
The RTD LEDs signal various statuses during start-up, as well as during operation. For explanation of the LED (LED 1 and LED 2) signals please see page 6 and respective figures in the Installation instructions.
Once communication over P1P2 between RTD-20 and indoor unit(s) has been established LED 3 should be flashing indicating that information is being exchanged between the RTD and the indoor unit(s).
Fault Signals
Generally, relay R2 signals a unit's fault - unless stated otherwise in the RTD-20 installation instructions. The exact fault code can be read either on the wired remote controller display or via Modbus (see the article RTD Fault Codes).
Testing
The RTD-20 can be tested with and without connecting an indoor unit. Testing can be performed via hardwired inputs (S1 - S6), as well as Modbus.
In Retail mode, please enter Engineer's mode for testing, maintenance and commissioning, as described on page 10 of the RTD-20 installation instructions.
If tests with Modbus are planned then do note that setting the RTD-20 to Retail mode means that the RTD-20 will operate as Modbus master, as described in the Modbus section above: In this case a Modbus gateway is required.
If no gateway is available then the RTD-20 can be set (for testing purposes) to a stand-alone operation mode in which case direct Modbus communication with the RTD-20 is possible (e.g. Partition Mode Slave: RTD-20: Individually control an indoor unit with Modbus). This would allow testing whether Modbus and P1P2 communication is operating correctly. You can use our free software ModTool for testing purposes: See the article ModTool Communication with our Products.
Note that if the RTD is not connected to any indoor unit then the parameters will be reset to default. When connected to an indoor unit then the values you have set will be stored.
If you have a remote controller and the RTD-20 on a P1P2 network and the RTD-20 is taken off the network (e.g. P1P2 disconnected or power switched off) then the remote controller can still operate (it needs to be in MAIN P1P2 mode though).