Wieland ricos FLEX BC MODBUS User Manual page 52

Overview
With the following Modbus function codes a Modbus master can access a Modbus slave. The descrip-
tion always takes place from the point of view of the master:
Code
01h
02h
03h
04h
05h
06h
0Fh
10h
16h
17h
Byte sequence in a word
High byte
Respond of the coupler
If the slave announces an error, the function code is sent back with a 'OR' and 80h. Without an error,
the function code is sent back.
Coupler answer
If the slave announces an error, the function code is sent back with a 'OR' and 80h. Without an error,
the function code is sent back.
01h: Function number is not supported
02h: Addressing errors
03h: Data errors
04h: ricos FLEX bus is not initialized
07h: General error
Read n Bits 01h, 02h
Code 01h: Read n bits of master output area 0x.
Code 02h: Read n bits of master input area 1x.
Command telegram
Modbus/TCP-Header Slave address
x x 0 0 0
6 byte
Respond telegram
Modbus/TCP-Header Slave
x x 0 0 0
6 byte
Wieland Electric GmbH | BA001269 | 09/2021 (Rev. A)
Command
Read n Bits
Read n Bits
Read n Words
Read n Words
Write 1 Bit
Write 1 Word
Write n Bits
Write n Words
Mask 1 Word
Write n words and read m words
1 word
Low byte
Function code OR 80h
Function code
6
1 byte
Function
address code
1 byte
Description
Read n bits of master output area 0x
Read n bits of master input area 1x
Read n words of master output area 4x
Read n words master input area 3x
Write 1 bit to master output area 0x
Write 1 word to master output area 4x
Write n bits to master area 0x
Write n words to master area 4x
Mask 1 word in master output area 4x
Write n words into master output area 4x and the re-
spond contains m read words of the master input area
3x
 Error & error number
 OK
Function code Address 1. bit
1 byte
Number of Data
read bytes 1. byte
1 byte 1 byte 1 byte
Deployment
Number of bits
1 word 1 word
Data ...
2. byte
1 byte
max. 252 byte
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