Danfoss VLT HVAC Basic Drive FC 100 Series Design Manual page 77

RS-485 Installation and Set...
Response
The normal response is an echo of the query, returned
after the coil state has been forced.
Field Name
Slave Address
Function
Force Data HI
Force Data LO
Quantity of Coils HI
Quantity of Coils LO
Error Check (CRC)
7.10.3 Force/Write Multiple Coils (0F HEX)
This function forces each coil in a sequence of coils to
either ON or OFF. When broadcast the function forces the
7 7
same coil references in all attached slaves.
The query message specifies the coils 17 to 32 (speed set-
point) to be forced.
NOTE
Coil addresses start at zero, i.e. coil 17 is addressed as 16.
Field Name
Slave Address
Function
Coil Address HI
Coil Address LO
Quantity of Coils HI
Quantity of Coils LO
Byte Count
Force Data HI
(Coils 8-1)
Force Data LO
(Coils 10-9)
Error Check (CRC)
Response
The normal response returns the slave address, function
code, starting address, and quantity of coiles forced.
Field Name
Slave Address
Function
Coil Address HI
Coil Address LO
Quantity of Coils HI
Quantity of Coils LO
Error Check (CRC)
76
VLT HVAC Basic Drive Design Guide
Example (HEX)
01
05
FF
00
00
01
-
Example (HEX)
01 (frequency converter address)
0F (write multiple coils)
00
10 (coil address 17)
00
10 (16 coils)
02
20
00 (ref. = 2000hex)
-
Example (HEX)
01 (frequency converter address)
0F (write multiple coils)
00
10 (coil address 17)
00
10 (16 coils)
-
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MG.18.C2.02 - VLT is a registered Danfoss trademark
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 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 - (3-03 Maximum Reference 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 000088B8 = 35.000 = 15Hz.
Field Name Example (HEX)
Slave Address 01
Function 03
Byte Count 04
Data HI 00
(Register 3030)
Data LO 16
(Register 3030)
Data HI E3
(Register 3031)
Data LO 60
(Register 3031)
Error Check -
(CRC)
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.