VIPA CPU 21 Series User Manual

Chapter 9 Deployment CPU 21xSER-1 Manual VIPA CPU 21x
9-28 HB103E - Rev. 05/45
The communication by Modbus knows 2 kinds of error:
• Slave doesn't respond to a master command
When the slave is not reacting within the defined timeout period, the
master writes the following error message into the receive block:
ERROR01 NO_DATA. In hex notation the following values are shown:
DB11.DBD 0
DW#16#4552524F
with 45 →
52 →
52 →
4F →
Respond telegram
E
R
R
O
DB11.DBD 4
DW#16#52000120
with 52 →
0001 →
20 →
Respond telegram
R
0001h:1 (as word)
" "
DB11.DBD 8
DW#16#4E4F2044
with 4E →
4F →
20 →
44 →
Respond telegram
N
O
" "
D
DB11.DBD 12
DW#16#41544100
with 41 →
54 →
41 →
00 →
Respond telegram
A
T
A
00h: (Zero scheduling)
• Slave answers with an error message
If the slave replies an error, the function code with 80h is send back
marked with an OR.
DB11.DBD 0
DW#16#05900000
with 05 →
90 →
0000 →
Respond telegram
slave address 05h
function code 90h (error message because
10h OR 80h = 90h)
rest data is irrelevant because an error was
announced
Receive block with
error respond

VIPA CPU 21 Series Specifications

General

Brand	VIPA
Model	CPU 21 Series
Category	Control Unit
Language	English