Sentera · Fan controller
RDCV9 digital residential fan speed controller Modbus register map
Default configuration
- Protocol
- RS485
- Port
- 502
- Unit ID
- 1
- Addressing
- 1-based
- Byte order
- Big endian
- Word order
- High word first
- Baud rate
- 19200
- Parity
- Even
- Data bits
- 8
- Stop bits
- 1
This device has an RS-485 interface. Reach it through a Modbus RTU-to-TCP gateway, configured with the factory serial settings above.
Register map
| Address | Count | Name | Type | Unit | Scale | Access |
|---|---|---|---|---|---|---|
| 1 | 1 | Output value 0...100 % output; 100 = 10 VDC / 20 mA / 100 % PWM, 50 = 5 VDC / 10 mA / 50 % PWM. | UInt16 | % | 1 | R |
| 2 | 1 | Output step Currently selected step, 0...9 (8 = step 8). | UInt16 | - | 1 | R |
| 3 | 1 | Output type 0 = 0...10 VDC, 1 = 0...20 mA, 2 = 0...100 % PWM. | UInt16 | - | 1 | R |
| 4 | 1 | Minimum output value 0...80 %; 20 = 2 VDC / 4 mA / 20 % PWM. | UInt16 | % | 1 | R |
| 5 | 1 | Maximum output value 20...100 %; 80 = 8 VDC / 16 mA / 80 % PWM. | UInt16 | % | 1 | R |
| 8 | 1 | Output overwrite mode 0 = manual, 1 = overwrite active. | UInt16 | - | 1 | R |
Read this device live with Modbus Connect, free for Windows, macOS and Linux
Related guides
Notes
Source: Sentera 'RDCV9 digital residential fan speed controller - Modbus register map', document code MBRM-RDCV9-EN-000 dated 18/03/2026, vendor-hosted PDF at https://www.sentera.eu/en/files/article/document/mbrm/rdcv9-ad-wh-modbus-register-map.pdf (SHA-256 a298ba3c5da3a868d1167bf43c3907a0e866e8b87a7a4f71612865ac2d944dbd; the black-enclosure copy at sentera.eu/nl/bestanden/artikel/document/mbrm/rdcv9-ad-bk-modbus-registermap.pdf is the same file) reached from the 'Modbus register map' link on the RDCV9 product page at the URL above (opened 7 Nov 2026): page 2 input registers, pages 3-4 holding registers. Factory settings from the holding-register table's 'Factory default values' column: slave address 1, baud rate 2 (19200 bps out of 0 = 4800, 1 = 9600, 2 = 19200, 3 = 38400, 4 = 57600, 5 = 115200, 6 = 230400), parity 1 (8E1 out of 0 = 8N1, 1 = 8E1, 2 = 8O1). Addressing: the map numbers its input registers 1...8 and holding registers 1...20 without a wire address or a frame example, which is the supplier's 1-based register numbering (Modbus register 1 = address 0x0000), so the seed declares one_based and stores the numbers exactly as printed. The document itself skips input registers 6 and 7 and holding registers 7 and 8 - those rows are not listed in the map and are not claimed here. The input-register block stops at 8 because 6 and 7 are absent. This is a fan-speed controller for EC/AC fans (0...10 VDC, 0...20 mA or PWM output) as used for the ventilation loops of small livestock rooms, sheds and stables; the holding register 13 maximum output and register 14 start output are the practical limits a barn ventilation curve is built on.