Appendix A. Modbus application
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Table A.2 Modbus errors
Code
Name
Description
01
Illegal Function
Function code received in the query is not recognized or
allowed by slave
02
Illegal Data Address
Data address of some or all the required entities are not
allowed or do not exist in slave
03
Illegal Data Value
Value is not accepted by slave
04
Slave Device Failure
Unrecoverable error occurred while slave was attempting
to perform requested action
07
Negative
Acknowledgement
(NAK)
The program function just requested cannot be performed
08
Memory Parity Error
Interface is used, when execution of the last command is
not yet completed
09
Custom error
Interface is used, when attempting to use RS1 with USB
already connected
Table A.3 RS1 (PC) interface*
No
Parameter
Register
Valid value
Description
Data type
Default
(Comment)
3 registers (R / W)
1
Baud rate
0x0000
0
1.2 kbit/s
UINT16
3 (16 kbit/s)
1
2.4 kbit/s
2
4.8 kbit/s
3
9.6 kbit/s
4
14.4 kbit/s
5
19.2 kbit/s
6
28.8 kbit/s
7
38.4 kbit/s
8
57.6 kbit/s
9
115.2 kbit/s
2
Device
address
0x0001
1…247
UINT16
16
3
Response
delay (ms)
0x0002
0…50 ms
UINT16
1
NOTE
* The request to change the parameters of the RS1 interface is responded with the same
interface parameters, the next one – with the new parameters.
