Rice Lake PR5220 Ethernet Transmitter - Manual (Page 119)

PR 5220 Instrument Manual J-Bus/ModBus Protocol
Sartorius EN-119
5.3 Functions
Function 1 or 2: Reading n Bits
Command Device
address Function
number Address of
1st bit Number of
bits
1 byte 1 byte 2 bytes 2 bytes
Range 1...127 1, 2 0, 8 , 16... 8, 16, 24...
The bit address must always be the 1st bit of a byte. The number of bits to be read may not be smaller than 8
and must be a multiple of 8.
Reply Device
address Function
number Number of
read bytes Value of 1st
byte Value of 2nd
byte
.. Value of last
byte
1 byte 1 byte 1 byte 1 byte 1 byte 1 byte
8. ...1. bit last bit
If the address of a bit to be read is out of the permissible range (0...127), an error message is sent as a reply
(the address plus the number of bits must not exceed 128).
Example of function 1 for reading the status bits of the scale (8 bits start at bit 32) with ModBus-TCP:
Command
47 11 0 0 0 6 0 1 0 32 0 8
Reply 47 11 0 0 0 4 0 1 1 X
The individual bytes are shown.
The read byte X
Bit 0 = bit 32 of SPM = ADC error
is interpreted as follows: Bit 1 = bit 33 of SPM = above Max (maximum capacity)
:
Bit 6 = bit 38 of SPM = weight is stable
Bit 7 = bit 39 of SPM = weight is below zero or above Max