Danfoss VLT Compressor Drive CDS 803 - Force;Write Multiple Coils (0 F Hex); Read Holding Registers (03 Hex)

Response
The normal response is an echo of the query, returned
after the coil state has been forced.
Field name Example (hex)
Slave address 01
Function 05
Force data HI FF
Force data LO 00
Quantity of coils HI 00
Quantity of coils LO 01
Error check (CRC) –
Table 7.25 Response
7.10.3 Force/Write Multiple Coils (0F hex)
Description
This function forces each coil in a sequence of coils to
either on or o. When broadcasting, the function forces
the same coil references in all attached slaves.
Query
The query telegram species the coils 17–32 (speed
setpoint) to be forced.
NOTICE
Coil addresses start at 0, that is, 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 (reference=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 telegram species the starting register and
quantity of registers to be read. Register addresses start at
0, that is, registers 1–4 are addressed as 0–3.
Example: Read parameter 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 D5 (Register address 3029)
Number of points HI 00
Number of points LO 02 – (parameter 3-03 Maximum
Reference is 32 bits long, that is, 2
registers)
Error check (CRC) –
Table 7.28 Query
Response
The register data in the response telegram is packed as 2
bytes per register, with the binary contents right justied
within each byte. For each register, the 1st byte contains
the high-order bits, and the 2nd contains the low-order
bits.
Example: hex 000088B8=35.000=35 Hz.
RS485 Installation and Set-... Design Guide
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