VRF HMI unit with touch buttons and Modbus interface RDF280 HMI for variable refrigerant flow (VRF) applications ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● A6V12071353_en--_b 2021-12-15 Slim (8 mm thickness) touch button design AC 230 V operating voltage, large LCD backlit display Operating modes: ON, OFF and ECO Room temperature or temperature setpoint display Room temperature display via built-in sensor or VRF indoor unit Temperature setpoint adjustment Minimum and maximum setpoint limitation Master/Slave VRF m
Use Room temperature control via connected VRF system Typical applications: ● Residential homes and apartments ● Offices & hotels For the VRF HMI, the unit interfaces with VRF systems via third-party gateway for: ● Setpoint adjustment: Maximum/minimum limitation ● Fan speed adjustment: Auto/manual speeds (max. 7 speeds) ● Operating mode selection: AUTO, HEAT, COOL, FAN and Dehumidification ● ECO mode: Energy saving ● Delay off timer (optional): Allow max.
Operating and setting elements Note Chinese text display can be disabled via P98. Symbol Description Symbol Description ECO mode Auto fan mode Manual fan mode Alarm/Service reminder Auto Cooling Heating Dehumidification Ventilation Delay-off timer Keylock Room temperature Secondary display Temperature, parameter values, etc.
Type summary Product no. Stock no. RDF280 S55770T442 Operating Description voltage Suitable for AC 230 V VRF HMI unit with touch button and Modbus interface Square conduit box Ordering When ordering, specify both product number / stock number and name: e.g.
● ● Recommended height: 1.5 m above the floor. Do not mount the devices in recesses, shelves, behind curtains or doors, or above or near heat sources. ● Avoid direct solar radiation and drafts. ● Avoid unheated (uncooled) building area such as outside walls. ● Seal the conduit box or the installation tube if any, as air currents can affect sensor readings. ● Adhere to allowed ambient conditions.
VRF error The error codes are displayed upon errors in the VRF indoor unit. For indoor unit error codes, see Control parameters [▶ 7]. Control parameters Parameter settings To optimize control performance, use the local HMI to enter parameter mode and adjust a number of control parameters. All control parameter settings are retained after power failure.
Press and hold the + and - buttons simultaneously for more than 3 seconds. Service level: Release the buttons, and within 2 seconds, press and hold + until Pxx is displayed. Expert level: Release the buttons, and within 2 seconds, press and hold - until Pxx is displayed. Press + or - (< or >) to access the desired parameter and the value of the selected parameter is displayed at the same time. Press (✓) to edit the value of the required parameter.
Parameter Description Factory setting Setting range P14 Keylock 0 0 = Unlock 1 = Setpoint & fan buttons adjustment only 2 = Full lock Note P27 Operating mode after power failure 0 0 = Previous operating mode 1 = OFF 2 = ON (Normal mode) P28 Timer with delay Off (0 up to 23 hours, 0.5 h) 1 0 = Disable 1 = Enable * The parameters are critical and must be set according to the equipment selected during commissioning.
For VRF mode, indicates Auto VRF mode, indicates ventilation and indicates cooling, indicates heating, indicates dehumidification. Setpoint adjustment and limitations The factory setting for the basic setpoint is 21 ℃. The setpoint can be adjusted via the +/buttons. The minimum (P09) and maximum (P10) setpoint limitations can be used to save energy.
– Use + or - to change the time up to 23 hours with a 0.5 h increment or decrement respectively. – Press (✓) to confirm the change. The device automatically exits delay Off timer mode or press ( ) to return to previous step. – Or press ( ) to exit delay Off timer mode without saving changes and to return to Normal mode. 3. Cancellation of timer with delay Off mode Cancel by setting the timer to 0 hour. 4.
● Note 1-to-n Modbus/VRF gateway with Modbus master function or an additional Modbus master unit The Modbus master manages communication between VRF HMI units (slave function) and the Modbus gateway to ensure proper operation. When using a Modbus gateway without Modbus master function, an additional Modbus master unit is required. RDF280 does not have termination resistor.
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Modbus interface Type Transmit mode Connection Baud rate Address Cable length Identity Transmission format (start bit – data – parity – stop) RS485 RTU Support up to 32 9600, 19200 (default), 38400, 57600 1...247, 247 (default) Max.1200 meters Slave 0 = 1-8-E-1 (default) / 1 = 1-8-O-1 / 2 = 1-8-N-1 / 3 = 1-8-N-2 Wiring connections Diameter Wire Max. 1.
Standards, directives and approvals Electromagnetic compatibility For residential, commercial, and industrial environments EU conformity (CE) A5W00161028A REACH Regulation (EC) No 1907/2006 Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) RoHS Directive 2011/65/EU restriction of the use of certain hazardous substances in electronic equipment Environmental compatibility The product environmental declaration (A5W00159015A *) contains data on environmentally compatible prod
Diagrams Connection terminals RDF280 L, N AC 230 V operating voltage A, B Modbus terminals, no isolation REF Modbus reference ground Connection diagrams RDF280 L, N AC 230 V operating voltage REF Modbus reference ground A+, B- Modbus terminals, no isolation 15 Siemens Smart Infrastructure A6V12071353_en--_b 2021-12-15
Modbus communication objects Description of communication objects Special Process Default 0001 1 RO 0x04 - 2 - - 0: OFF 1: ON (Normal mode) 2: ECO 2 Current VRF mode 0002 1 RO 0x04 - 2 - - 0: AUTO 1: COOL 2: HEAT 3: Dehumidification 4: FAN 3 Fan seed setting status 0003 1 RO 0x04 - 2 - - 0: AUTO 1: Fan speed 1 2: Fan speed 2 3: Fan speed 3 4: Fan speed 4 5: Fan speed 5 6: Fan speed 6 7: Fan speed 7 4 Room temperature 0004 1 RO 0x04 - 2 x50 - -10...
Read Only (RO) or Read/Write (R/W) 0006 1 RO 13 Indoor unit On/Off command 0010 1 14 VRF mode 0011 15 Setpoint temperature 16 - 2 - 0 0: OK 1: Error R/W 0x03 0x06 or 0x10 3 - 1 0: OFF 1: ON (Normal mode) 2: ECO 1 R/W 0x03 0x06 or 0x10 3 - 0 0: AUTO 1: COOL 2: HEAT 3: Dehumidification 4: FAN 0012 1 R/W 0x03 0x06 or 0x10 3 x50 - 5...35 ℃ Room temperature from VRF indoor unit 0013 1 R/W 0x03 0x06 or 0x10 3 x50 - -10...
Read Only (RO) or Read/Write (R/W) Multi-Bytes Access Group Special Process Default P06 0035 1 R/W 0x03 0x06 or 0x10 4 - 0 0 = Room temperature 1 = Setpoint 2 = BUS temperature 26 P08 0036 1 R/W 0x03 0x06 or 0x10 4 x50 21 ℃ 5…40 ℃ 27 P09 0037 1 R/W 0x03 0x06 or 0x10 4 x50 5℃ 5 ℃…P10 (P10 = 40 ℃ max.) 28 P10 0038 1 R/W 0x03 0x06 or 0x10 4 x50 35 ℃ (P09 = 5 ℃ min.
Dimensions (mm) 19 Siemens Smart Infrastructure A6V12071353_en--_b 2021-12-15
Issued by Siemens Switzerland Ltd Smart Infrastructure Global Headquarters Theilerstrasse 1a CH-6300 Zug +41 58 724 2424 www.siemens.com/buildingtechnologies Document ID A6V12071353_en--_b Edition 2021-12-15 © Siemens Switzerland Ltd, 2021 Technical specifications and availability subject to change without notice.
