Danfoss VLT HVAC Design Guide

7.10.4 Read Holding Registers (03 HEX)
Description
This function reads the contents of holding registers in the slave.
Query
The query message specifies the starting register and quantity of registers to be read. Register addresses start at zero, i.e. registers 1-4 are addressed
as 0-3.
Example: Read par. 3-03,
Maximum Reference , register 03030.
Field Name Example (HEX)
Slave Address 01
Function 03 (read holding registers)
Starting Address HI 0B (Register address 3029)
Starting Address LO 05 (Register address 3029)
No. of Points HI 00
No. of Points LO 02 - (Par. 3-03 is 32 bits long, i.e. 2 registers)
Error Check (CRC) -
Response
The register data in the response message are packed as two bytes per register, with the binary contents right justified within each byte. For each register,
the first byte contains the high order bits and the second contains the low order bits.
Example: Hex 0016E360 = 1.500.000 = 1500 RPM.
Field Name Example (HEX)
Slave Address 01
Function 03
Byte Count 04
Data HI
(Register 3030)
00
Data LO
(Register 3030)
16
Data HI
(Register 3031)
E3
Data LO
(Register 3031)
60
Error Check
(CRC)
-
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Danfoss VLT HVAC Specifications

General

Enclosure Rating	IP20, IP21, IP54, IP55, IP66
Storage Temperature Range	-25°C to +70°C
Output Voltage Range	0-100% of supply voltage
Communication Protocols	Modbus RTU, BACnet, Ethernet/IP, Profibus DP
Ambient Temperature Range	-10°C to +50°C (without derating)
Relative Humidity	5% to 95% non-condensing
Altitude	Up to 1000 m without derating
Cooling Method	Air cooled
Application	HVAC systems, Pumps, Fans, Compressors
Voltage Range	200-240 V, 380-500 V, 525-600 V
Frequency Range	0 Hz to 590 Hz