Danfoss iC2 Application Manual page 91

Application Guide | iC2-Micro Frequency Converters
Table 39: Query
Field name
Follower address
Function
Starting address HI
Starting address LO
Number of points HI
Number of points LO
Error check (CRC)
Response
The coil status in the response telegram is packed as 1 coil per bit of the data field. Status is indicated as: 1 = ON; 0 = OFF. The lsb of the
1st 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 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 40: Response
Field name
Follower address
Function
Byte count
Data (coils 40–33)
Data (coils 48–41)
Error check (CRC)
Coils and registers are addressed explicitly with an offset of -1 in Modbus. For example, coil 33 is addressed as coil 32.
Read Holding Registers (03 hex)
6.1.7.6.2
Description
This function reads the contents of holding registers in the follower.
Query
The query telegram 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 P 5.5.3.3 Reference Maximum, register 3029. The parameter number is 303.
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Example (hex)
01 (drive address)
01 (read coils)
00
20 (32 decimals) coil 33
00
10 (16 decimals)
–
Example (hex)
01 (drive address)
01 (read coils)
02 (2 bytes of data)
07
06 (STW = 0607hex)
–
NOTICE
AB413939445838en-000301 / 130R1254 |
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