Specifications

72
Schneider Electric
The Modbus Protocol (continued)
Write n consecutive bits: function 15
b Query.
b Response.
Example:
Force bits 200 and 201 of slave 3 to 1.
b Query.
b Response.
If the slave number is 0, all slaves perform
the write operation but do not return a
response.
E52384E52385E52386E52387
Slave no.
OF
Address of
the 1st bit to
force
No. of bits
to force
CRC 16
1 byte 1 byte 2 bytes 2 bytes2 bytes
No. of bytes
to force
Value of
bits to
force
1 byte n bytes
Last bit of
1st byte
1st bit of
1st byte
First bit of
nth byte
1st byte nth byte
Last bit of
nth byte
1
n 246
1
X 1968
Slave no.
OF
Address of
the 1st bit
forced
No. of bits
forced
CRC 16
1 byte 1 byte 2 bytes 2 bytes 2 bytes
CRC 16
3 OF 200 0002 01 03
CRC 16
3 OF 200 0002
Guide to Integration
Modbus / Jbus