NOTICE
Coils and registers are addressed explicitly with an off-
set of -1 in Modbus.
i.e. Coil 33 is addressed as coil 32.
5.10.2 Force/Write Single Coil (05 hex)
Description
This function forces the coil to either ON or OFF. When
broadcast, the function forces the same coil references in
all attached slaves.
Query
The query message specifies the coil 65 (parameter write
control) to be forced. Coil addresses start at 0, that is, coil
65 is addressed as 64. Force Data=00 00hex (OFF) or FF
00hex (ON).
Field name
Example (hex)
Slave address
01 (Frequency converter address)
Function
05 (write single coil)
Coil address HI
00
Coil address LO
40 (64 decimal) Coil 65
Force data HI
FF
Force data LO
00 (FF 00=ON)
Error check (CRC)
-
Table 5.24 Query
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 5.25 Response
5.10.3 Force/Write Multiple Coils (0F hex)
Description
This function forces each coil in a sequence of coils to
either
on
or
off
. When broadcasting, the function forces
the same coil references in all attached slaves.
Query
The query message specifies the coils 17 to 32 (speed set-
point) to be 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)
Byte count
02
Force data HI
(Coils 8-1)
20
Force data LO
(Coils 16-9)
00 (ref.=2000 hex)
Error check (CRC)
–
Table 5.26 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 5.27 Response
5.10.4 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
0, that is, 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
D5 (Register address 3029)
Number of points HI
00
Number of points LO
02 - (
3-03 Maximum Reference
is 32 bits
long, i.e. 2 registers)
Error xheck (CRC)
–
Table 5.28 Query
RS485 Installation and Set-...
Design Guide
72
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MG06B402
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