CAREL · Chiller controller
µChiller chiller / heat pump controller Modbus register map
Default configuration
- Protocol
- RS485
- Port
- 502
- Unit ID
- 1
- Addressing
- 0-based
- Byte order
- Big endian
- Word order
- High word first
- Baud rate
- 115200
- Parity
- None
- Data bits
- 8
- Stop bits
- 2
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 |
|---|---|---|---|---|---|---|
| 19 | 1 | Free-Cooling enable U068 - Enable Free-Cooling (0=Disabled, 1=Enabled) | UInt16 | - | 1 | RW |
| 22 | 1 | Capacity request from BMS enable Hd06 - Enable capacity request from BMS (0=Disabled, 1=Enabled) | UInt16 | - | 1 | RW |
| 46 | 1 | Source type S068 - Source type (0=Air, 1=Water) | UInt16 | - | 1 | RW |
| 47 | 1 | Unit of measure (display and BMS) UoM - Unit of measure used for Display 2-Row and BMS, not for Applica (0=°C/bar, 1=°F/PSI) | UInt16 | - | 1 | RW |
| 48 | 1 | BMS port database type Hd07 - BMS port database type (0= 32bit, 1= 16bit) | UInt16 | - | 1 | RW |
| 54 | 1 | Unit ON/OFF command from keypad UnSt - Unit ON/OFF command from keypad (0=OFF 1=ON) | UInt16 | - | 1 | RW |
| 55 | 1 | Cool/Heat mode from keypad ModE - Cool/Heat mode from keypad (0=Cool, 1=Heat) | UInt16 | - | 1 | RW |
| 56 | 1 | Reset active alarms from BMS RES - Reset active alarms from BMS net (0=NO, 1=Reset) | UInt16 | - | 1 | RW |
| 59 | 1 | Delete alarms log ClrH - Delete alarms log (0=No, 1=Yes) | UInt16 | - | 1 | RW |
| 63 | 1 | Unit ON/OFF command by BMS enable Hd05 - Enable unit ON/OFF command by BMS net (0=Disabled, 1=Enabled) | UInt16 | - | 1 | RW |
| 64 | 1 | Unit ON/OFF command from BMS Unit On/Off command from BMS (0=OFF, 1=ON) | UInt16 | - | 1 | RW |
Read this device live with Modbus Connect, free for Windows, macOS and Linux
Related guides
Notes
Source: CAREL "Chiller - Controller for Chiller / Heat Pump, User Manual", +0300053EN rel. 2.4, 09.10.2023 (the revision the cited URL serves; version=1.16 serves rel. 2.5, 03.10.2024), sections 6.8 (BMS port) and 7 (Supervisor table) (https://www.carel.com/documents/10191/0/+0300053EN/36cc33b9-4225-46cc-91aa-734d126b5dcb?version=1.14). Section 7 defines the supervisor database as Modbus RTU over the controller's RS-485 BMS port with factory settings 115,200 bps, 8 data bits, no parity, 2 stop bits, serial address 1 (parameters Hd00/Hd01/Hd02, section 6.8) and states that the table's "Index" is the address specified in the Modbus frame, so the addresses here are wire addresses and the file declares zero_based addressing. The database is 32-bit per Hd07 default 0, so REAL values are IEEE-754 single precision in two registers and UINT values one register. Register numbers shown in the manual's parameter tables (for example HR 147 = serial address) are the supervisor-table indexes of the same variables. Coil and input-status points are bit-addressed in the controller and are listed as one-register values here. Only a working subset of the supervisor table is included: the temperature/pressure probes and alarms that a first integration needs, plus the BMS-port settings. 32-bit hour counters and the secondary-board registers are left out, as is HR 331 (BMS_PwrReq, the BMS capacity request), which section 7.2 does list as a REAL written to two registers big-endian without swap - it is a scope choice, not a missing data type.