If the returned coil quantity is not a multiple of 8, the remaining bits in the final data byte are padded with values 0 (toward the
high-order end of the byte). The byte count field specifies the number of complete bytes of data.
Table 71: Response
Field name
Example (hex)
Follower address
01 (drive 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)
–
N O T I C E
Coils and registers are addressed explicitly with an offset of -1 in Modbus. For example, coil 33 is addressed as coil 32.
8.10.3 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 follow-
ers.
Query
The query telegram 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 00 hex (OFF) or FF 00 hex (ON).
Table 72: Query
Field name
Example (hex)
Follower address
01 (drive 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)
–
Response
The normal response is an echo of the query, returned after the coil state has been forced.
Table 73: Response
Field name
Example (hex)
Follower address
01
Function
05
Force data HI
FF
Force data LO
00
AJ363928382091en-000101 / 130R0983
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RS485 Installation and Set-up
VLT® Flow Drive FC 111
Design Guide
