Rice Lake PR5230 Fieldbus Transmitter - 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.