Function 8: diagnosis, Function 15: writing n successive bits, Pr 5230 instrument manual j-bus/modbus protocol – Rice Lake PR5230 Fieldbus Transmitter User Manual
Page 173
PR 5230 Instrument Manual
J-Bus/ModBus Protocol
Sartorius
EN-173
Function 8: Diagnosis
Command
Device address
Function
number
Sub-function
Any value
1 byte
1 byte
2 bytes
2 bytes
Range
1...127
8
0
This function is intended for testing the communication.
Only sub-function 0 is supported.
The received command is sent as a reply.
Reply
Device address
Function
number
Sub-function
Value of the
command
1 byte
1 byte
2 bytes
2 bytes
Function 15: Writing n Successive Bits
Command
Device
address
Function
number
Address of
the 1st bit
Number of
bits
Number of
bytes
Value of bits
1 byte
1 byte
2 bytes
2 bytes
1 byte
n bytes
Range
0...127
15
0...127
8, 16, 24
1, 2, 3...
1
st
byte
2
nd
byte
3
rd
byte
- - - - - - - - - - last byte
8
th
... 1
st
bit
last bit
The bit address must always be the 1st bit of a byte. The number of bits to be read must not be smaller than 8
and must be a multiple of 8. The address plus the number of bits must not exceed 128.
Reply
Device address
Function
number
Address of the
1st bit
Number of bits
1 byte
1 byte
2 bytes
2 bytes
Example of function 15 with ModBus-RTU:
Command
1
15
0
64
0
8
1
3
CRC CRC
Reply
1
15
0
64
0
8
CRC CRC
Example with ModBus-TCP:
Command
47
14
0
0
0
8
0
15
0
64
0
8
1
3
Reply
47
14
0
0
0
6
0
15
0
64
0
8
The individual bytes are shown.