ModBus Protocol
PR 5500 Instrument Manual
EN-424 Sartorius
Function 3 or 4: read n successive words
Command
Function
number
Address of
1st word
Number of
words
1 byte
2 bytes
2 bytes
Value range
3, 4
0 to 63
1 to 64
Reply
Function
number
Number of
bytes
Value of
words
1 byte
1 byte
n bytes
MSB
LSB
MSB
- - - - - - -
MSB
LSB
1st word
Last word
If the address of one of the words to be read is out of the permissible range (0 to 16383), an error message is
sent as a reply (the address plus the number of words must not exceed 16384).
The number of words is limited by the telegram to 125 words (250 bytes). If there are more than 125 words, then
an error telegram is sent as a reply.
Example of function 3 for reading a gross weight (D8 = W16) of 893 kg with ModBus-RTU:
Command
1
3
0
16
0
2
CRC
CRC
Reply
1
3
4
0
0
3
125
CRC
CRC
Example with ModBus-TCP:
Command
47
12
0
0
0
6
0
3
0
16
0
2
Reply
47
12
0
0
0
7
0
3
4
0
0
3
125
The individual bytes are shown.
Summary of Contents for Sartorius Intec Maxxis 4 PR 5500
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