Vertiv · CRAH
Liebert CRAH (CW / PDX / PCW) with IntelliSlot Unity card Modbus register map
Default configuration
- Protocol
- Modbus TCP
- Port
- 502
- Unit ID
- 1
- Addressing
- 1-based
- Byte order
- Big endian
- Word order
- High word first
Register map
| Address | Count | Name | Type | Unit | Scale | Access |
|---|---|---|---|---|---|---|
| 13 | 1 | Minimum chilled water temperature set point enable 0 = Disabled, 1 = Enabled. | UInt16 | - | 1 | RW |
| 19 | 1 | Return air sensor event control 0 = Disabled, 1 = Enabled. Enables the return air sensor alarm handling. | UInt16 | - | 1 | RW |
| 20 | 1 | Ext air sensor A event control 0 = Disabled, 1 = Enabled. | UInt16 | - | 1 | RW |
| 25 | 1 | System on/off control 0 = Off, 1 = On. Switches the cooling unit on or off from the BMS. | UInt16 | - | 1 | RW |
Notes
The Modbus TCP server is the Liebert IntelliSlot Unity card (IS-UNITY-DP) fitted to the unit; it listens on port 502 and its device/unit identifier is set on the card's web interface (1 by default). The tables cover the Liebert iCOM cooling units with iCOM v4 firmware PA1.04.033.STD or later (CW, CWA, PDX/PCW and related CRAH families) as published by Vertiv; which points are actually present depends on the unit configuration (chilled water or DX, economizer, humidifier, reheat, static pressure control). Numbering follows Vertiv's register table without its Modicon area prefix (discrete input 10025 is listed as 25, input register 30100 as 100, holding register 40019 as 19), one-based, so the wire address is the number minus one - this file therefore declares one_based addressing. Values whose scale column says 10 are transmitted as ten times the engineering value, hence scale 0.1. Input registers that mirror settings are read-only images; write the holding register of the same name to change a setpoint.