Write One Bit - JUMO LOGOSCREEN nt Interface Description

4 Modbus protocol description

4.6.3 Write one bit

Instruction
Response
Example
20
Data request:
01 03 1257
Response:
01 03 0C 1999
Measurement 1
200.1
For the "Write one bit" function, the data blocks for instruction and
response are identical.
Slave Function
address 0x05
1 byte 1 byte
Slave Function
address 0x05
1 byte 1 byte
Write one bit, at bit address 0x0340 (i.e. bit 0 of the word address 0x0034).
For addresses, see Chapter 7.1 Modbus addresses for important device and
process data, page 43.
Instruction:
01 05 0340
Response (as instruction):
01 05 0340
0006 7160
4348 4CCC 4348
Measurement 2
200.3
Bit address
2 bytes
Bit address
2 bytes
FF00 8DAA
FF00 8DAA
2666 4396
Measurement 3
300.3
Bit value Checksum
xx00 CRC16
2 bytes 2 bytes
!
xx = 00 bit
is set to 0
!
xx = FF bit
is set to 1
Bit value Checksum
CRC16
2 bytes 2 bytes
8548