Command telegram
Slave address
Function code
Address 1. bit
Number of bits
Check sum
CRC/LRC
1byte
1byte
1word
1word
1word
Respond telegram
Slave address Function code
Number of
read bytes
Data 1. byte
Data 2. byte
...
Check sum
CRC/LRC
1byte
1byte
1byte
1byte
1byte
1word
max. 250byte
03h: Read n words of master output area 4x
04h: Read n words master input area 3x
Command telegram
Slave address
Function code
Address 1. bit
Number of words
Check sum
CRC/LRC
1byte
1byte
1word
1word
1word
Respond telegram
Slave address Function code
Number of
read bytes
Data 1. word
Data 2. word
...
Check sum
CRC/LRC
1byte
1byte
1byte
1word
1word
1word
max. 125words
Code 05h: Write 1 bit to master output area 0x
A status change is via "Status bit" with following values:
"Status bit" = 0000h
®
Bit = 0
"Status bit" = FF00h
®
Bit = 1
Command telegram
Slave address
Function code
Address bit
Status bit
Check sum
CRC/LRC
1byte
1byte
1word
1word
1word
Respond telegram
Slave address
Function code
Address bit
Status bit
Check sum
CRC/LRC
1byte
1byte
1word
1word
1word
Read n words 03h, 04h
Write 1 bit 05h
System 300S
+
Deployment PtP communication
Modbus - Function codes
HB140 | CPU | 315-4PN23 | en | 18-02
86