modbus_write_bits

 

Function

 

Uses the function code Write Multiple Coils (code 15) to write multiple bits to the Coil area.

 

Format

 

ret = modbus_write_bits( ctx , addr , nb , data )

 

Parameters

 

ctx [ VB.NET： IntPtr ] [ C, C++： modbus_t * ] [ C#： IntPtr ] [ Python： ctypes.POINTER(modbus_t) ]

Specify the pointer to the libmodbus structure.

 

addr [ VB.NET： Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_int ]

Specify the start address to write.

 

nb [ VB.NET： Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_int ]

Specify the number of bits to write.

 

data [ VB.NET：Byte() ] [ C, C++： uint8_t * ] [ C#： byte[] ] [ Python： ctypes.POINTER(ctypes.c_uint8) ]

Specify the start address of the array that has stored the data to be written.

 

Return values

 

ret [ VB.NET：Integer ] [ C, C++： int ] [ C#： int ] [ Python： ctypes.c_int ]

 

If the function succeeds, the number of bits that were successfully written is returned.

If the function fails, -1 is returned, and the following errno is set.

 

Definition

Description

EMBMDATA

The number of request data is too large.

 

Remarks

 

Uses the function code Write Multiple Coils (code 15) to write multiple bits to the Coil area.

 

Example

 

Writes 1 for 8 bits from address 0.

 

VB.NET

Dim ret As Integer

Dim ctx As IntPtr

Dim data(8) As Byte

Dim i As Short

For i = 0 To 7

     data(i) = 1

Next i

ret = modbus_write_bits(ctx, 0, 8, data)

 

C, C++

int ret;

modbus_t *ctx;

uint8_t data[8];

short i;

for( i = 0 ; i < 8 ; i++ ){

     data[i] = 1;

}

ret = modbus_write_bits( ctx, 0, 8 , data );

 

C#

int ret;

IntPtr ctx;

byte[] data = new byte[8];

short i;

for( i = 0 ; i < 8 ; i++ ){

     data[i] = 1;

}

ret = modbus.WriteBits(ctx, 0, 8, data);

 

Python

ret = ctypes.c_int

ctx = ctypes.POINTER(modbus_t)

uint8_buff_type = ctypes.c_uint8 * 8

data = uint8_buff_type()

for i in range(8):

       data[i] = 1

ret = modbus.modbus_write_bits(ctx, 0, 8, data)