Download CFW700 - Modbus RTU

Detailed Description of the Functions
Example: writing of 900 rpm as the speed reference (P0683) (assuming a synchronous speed of 1800 rpm) for
the slave at address 3.
ƒ Address: 3 = 03h (1 byte)
ƒ Parameter number: 683 = 02AB (2 bytes)
ƒ Value for parameter: 1000h (2 bytes)
Request (Master)
Response (Slave)
Field
Value
Field
Value
Slave Address
Function
Register (high)
Register (low)
Value (high)
Value (low)
CRCCRC+
03h
06h
02h
ABh
10h
00h
F5h
B0h
Slave Address
Function
Register (high)
Register (low)
Value (high)
Value (low)
CRCCRC+
03h
06h
02h
ABh
10h
00h
F5h
B0h
Note that for this function the slave response is an identical copy of the request made by the master.
6.3
FUNCTION 16 – WRITE MULTIPLE REGISTERS
This function allows writing values for a group of registers, which must be in a numerical sequence. It can also
be used to write in a single register (each field represents a byte):
Request (Master)
Slave Address
Function
Initial register address (high byte)
Initial register address (low byte)
Number of registers (high byte)
Number of registers (low byte)
Byte count (number of data bytes)
Datum 1 (high)
Datum 1 (low)
Datum 2 (high)
Datum 2 (low)
etc...
CRCCRC+
Response (Slave)
Slave Address
Function
Initial register address (high byte)
Initial register address (low byte)
Number of registers (high byte)
Number of registers (low byte)
CRCCRC+
Example: writing of the acceleration time (P0100) equal to 1.0s and the deceleration time (P0101) equal to 2.0s,
of a slave at address 15.
ƒ Address: 15 = 0Fh (1 byte)
ƒ First parameter number: 100 = 0064h (2 bytes)
ƒ Value for the fist parameter: 10 = 000Ah (2 bytes)
ƒ Value for the second parameter: 20 = 0014h (2 bytes)
Request (Master)
Field
Slave Address
Function
Initial register (high)
Initial register (low)
Number of registers (high)
Number of registers (low)
Byte count
P0100 (high)
P0100 (low)
P0101 (high)
P0101 (low)
CRCCRC+
Response (Slave)
Value
0Fh
10h
00h
64h
00h
02h
04h
00h
0Ah
00h
14h
E0h
91h
Field
Slave Address
Function
Initial register (high)
Initial register (low)
Number of registers (high)
Number of registers (low)
CRCCRC+
Value
0Fh
10h
00h
64h
00h
02h
01h
39h
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