FC101 Design Guide

7.10.1 Read Coil Status (01 hex)
Description
This function reads the ON/OFF status of discrete outputs
(coils) in the frequency converter. Broadcast is never
supported for reads.
Query
The query telegram species the starting coil and quantity
of coils to be read. Coil addresses start at 0, that is, coil 33
is addressed as 32.
Example of a request to read coils 33–48 (status word)
from slave device 01.
Field name Example (hex)
Slave address 01 (frequency converter address)
Function 01 (read coils)
Starting address HI 00
Starting address LO 20 (32 decimals) coil 33
Number of points HI 00
Number of points LO 10 (16 decimals)
Error check (CRC) –
Table 7.22 Query
Response
The coil status in the response telegram is packed as 1 coil
per bit of the data eld. Status is indicated as: 1 = ON; 0 =
OFF. The lsb of the rst data byte contains the coil
addressed in the query. The other coils follow toward the
high-order end of this byte, and from low order to high
order in subsequent bytes.
If the returned coil quantity is not a multiple of 8, the
remaining bits in the nal data byte are padded with
values 0 (toward the high-order end of the byte). The byte
count eld species the number of complete bytes of data.
Field name Example (hex)
Slave address 01 (frequency converter address)
Function 01 (read coils)
Byte count 02 (2 bytes of data)
Data (coils 40–33) 07
Data (coils 48–41) 06 (STW = 0607hex)
Error check (CRC) –
Table 7.23 Response
NOTICE!
Coils and registers are addressed explicitly with an o-
set of -1 in Modbus.
For example, coil 33 is addressed as coil 32.
7.10.2 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 telegram species 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 00 hex (OFF) or FF
00 hex (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 7.24 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 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.
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