130 Chapter 8 - Modbus RTU Protocol
User Manual
Example: Modbus
Drive address 10 (0A
hex
)
Coil 1186 (04A2
hex
)
ADDR FUNC
DATA
DATA
DATA
DATA
CRC
CRC
start
start
bit# bit#
Addr HI Addr LO HI
LO
HI
LO
0A
01
04
A1
00
01
AC 63
Response
The request refers to the content of the Coil 1185 which does not exist in the Drive slave. The slave answers with
the error code 02 (ILLEGAL DATA ADDRESS) and goes back to the function code 81h (129).
Example: Exception to the above mentioned request.
ADDR FUNC
DATA
CRC
CRC
Except.
Code HI
LO
0A
81
02
B0
53
8.5.1 Exception codes
This protocol implementation foresees only four exception codes:
Code
Name
Meaning
01 ILLEGAL FUNCTION
The received function code does not correspond to a function allowed on the addressed slave.
02 ILLEGAL DATA ADDRESS
The address number, which the data field refers to, is not a register allowed on the addressed slave.
03 ILLEGAL DATA VALUE
The value to be allocated, which the data field refers to, is not allowed for this register.
07 NAK - NEGATIVE
The function can not be performed with the present operating
ACKNOWLEDGEMENT
conditions or attempt to write an only-reading parameter.
8.6 System configuration
In order to select the configuration of the serial line, the AGy drives of are supplied in the main INTERFACE menu with a
submenu called Serial config; some parameters are common to the different kinds of implemented protocols (fOX LINK,
Modbus, etc); the menu contains the following parameters:
Code
LCD display
[Code] & LCD select.
Default
MIN
MAX
Unit
Variation
IPA
I.600
Serial link cfg
[0] FoxLink 7E1
4
0
5
155
[1] FoxLink 701
[2] FoxLink 7N2
[3] FoxLink 8N1
[4] ModBus 8N1
[5] JBus 8N1
I.601
Serial link bps
[0] 600 baud
4
0
9
156
[1] 1200 baud
[2] 2400 baud
[3] 4800 baud
[4] 9600 baud
[5] 19200 baud
[6] 38400 baud
[7] 57600 baud
[8] 76800 baud
[9] 115200 baud
I.602
Device address
0
0
99
1
157
I.603
Ser answer delay
1
0
250
msec
1
158
I.604
Serial timeout
0
0
25
sec
0,1
159
I.605
En timeout alm
[0] Disable
160
[1] Enable
