Specifications

NOTICE
Coil addresses start at zero, i.e.
coil 17 is addressed as 16.
Field Name Example (HEX)
Slave address 01 (frequency converter address)
Function 0F (write multiple coils)
Coil address HI 00
Coil address LO 10 (coil address 17)
Quantity of coils HI 00
Quantity of coils LO 10 (16 coils)
Byte count 02
Force data HI
(Coils 8-1)
20
Force data LO
(Coils 16-9)
00 (ref. = 2000 hex)
Error check (CRC) -
Table 7.26 Query
Response
The normal response returns the slave address, function
code, starting address, and quantity of coils forced.
Field Name Example (HEX)
Slave address 01 (frequency converter address)
Function 0F (write multiple coils)
Coil address HI 00
Coil address LO 10 (coil address 17)
Quantity of coils HI 00
Quantity of coils LO 10 (16 coils)
Error check (CRC) -
Table 7.27 Response
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, so registers 1-4 are addressed as 0-3.
Example: Read F-53 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 D5 (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) -
Table 7.28 Query
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)
-
Table 7.29 Response
7.10.5 Preset Single Register (06 HEX)
Description
This function presets a value into a single holding register.
Query
The query message specifies the register reference to be
preset. Register addresses start at zero, i.e. register 1 is
addressed as 0.
Example: Write to 1-00 Configuration Mode, register 1000.
Installation and Set-up VLT® HVAC Drive FC 102 Design Guide
176 MG16C102 - Rev. 2013-08-20
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