Burkert Type 8717 - Manual (Page 69)

69
Starting up the Modbus
Response
field name value
Slave address 0x01
Function 0x84
data field 0x02
Error check CRC (high byte)
Error check CRC (low byte)
In this example the master addresses a request to slave device 01. The function code 04 stands for “Read Input
Register”. The register address in the device is outside the address validity range and this is why the slave sends
an exceptional reply with the indicated exception code 02 (Illegal data Address).
implemented exceptional replies
code name Description
00 Not an error
01 ILLEGAL FUNCTION Function code is not supported
02 ILLEGAL dATA AddRESS The data address is not permitted in the device
03 ILLEGAL dATA VALUE A value included in the request field is incorrect for the
device
04 SLAVE dEVICE FAILURE Internal device error
Number formats
Data type Description length
(bytes)
UINT8 Unsigned integer, 8 bit 1
UINT16 Unsigned integer, 16 bit 2
UINT32 Unsigned integer, 32 bit 4
FLOAT32 Floating-point number in accordance with IEEE-754
The Float32 value is saved in two successive addresses, the first address
includes the most significant word (sign, exponent, and upper part of the man-
tissa), and the second address the least significant word (lower part of the
mantissa) 4
More technical information can be found at www.modbus.org.
english
MFC Family