Specifications
7.10.3 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 followers.
Query
The query message specifies the coils 17 to 32 (speed set-
point) to be forced.
Field Name Example (HEX)
Follower 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 7.25 Query
Response
The normal response returns the follower address, function
code, starting address, and quantity of coils forced.
Field Name Example (HEX)
Follower 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 7.26 Response
7.10.4
Read Holding Registers (03 HEX)
Description
This function reads the contents of holding registers in the
follower.
Query
The query message specifies the starting register and
quantity of registers to be read. Register addresses start at
zero, that is, registers 1-4 are addressed as 0-3.
Example: Read 3-03 Maximum Reference, register 03030.
Field Name Example (HEX)
Follower Address 01
Function 03 (read holding registers)
Starting Address HI 0B (Register address 3029)
Starting Address LO 05 (Register address 3029)
No. of Points HI 00
No. of Points LO
02 - (3-03 Maximum Reference is 32 bits
long, i.e. 2 registers)
Error Check (CRC) -
Table 7.27 Query
Response
The register data in the response message are packed as 2
bytes per register, with the binary contents right justified
within each byte. For each register, the first byte contains
the high-order bits and the second contains the low-order
bits.
Example: Hex 000088B8=35.000=15 Hz.
Field Name Example (HEX)
Follower Address 01
Function 03
Byte Count 04
Data HI (Register 3030) 00
Data LO (Register 3030) 16
Data HI (Register 3031) E3
Data LO (Register 3031) 60
Error Check (CRC) -
Table 7.28 Response
7.10.5
Preset Single Register (06 HEX)
Description
This function presets a value into a single holding register.
Query
The query message specifies the register reference to be
preset. Register addresses start at zero, that is, register 1 is
addressed as 0.
Example: Write to 1-00 Configuration Mode, register 1000.
Field Name Example (HEX)
Follower Address 01
Function 06
Register Address HI 03 (Register address 999)
Register Address LO E7 (Register address 999)
Preset Data HI 00
Preset Data LO 01
Error Check (CRC) -
Table 7.29 Query
RS-485 Installation and Set...
VLT
®
HVAC Basic Drive FC 101 Design Guide
MG18C502 - Rev. 2013-09-06 93
7 7