Bus adress Bus register
1
PLC Register Content
Access
Description
0
1
40001
Reserved
Reserved for Legacy Drives VLT 5000 and VLT 2800
1
2
40002
Reserved
Reserved for Legacy Drives VLT 5000 and VLT 2800
2
3
40003
Reserved
Reserved for Legacy Drives VLT 5000 and VLT 2800
3
4
40004
Free
4
5
40005
Free
5
6
40006
Modbus conf
Read/Write
TCP only. Reserved for Modbus TCP (p12-28 and 12-29 -
store in Eeprom etc.)
6
7
40007
Last error code
Read only
Error code recieved from parameter database, refer to
WHAT 38295 for details
7
8
40008
Last error register Read only
Address of register with which last error occurred, refer
to WHAT 38296 for details
8
9
40009
Index pointer
Read/Write
Sub index of parameter to be accessed. Refer to WHAT
38297 for details
9
10
40010
FC par. 0-01
Dependent on
parameter access
Parameter 0-01 (Modbus Register=10 parameter number
20 bytes space reserved pr parameter in Modbus Map
19
20
40020
FC par. 0-02
Dependent on
parameter access
Parameter 0-02
20 bytes space reserved pr parameter in Modbus Map
29
30
40030
FC par. xx-xx
Dependent on
parameter access
Parameter 0-03
20 bytes space reserved pr parameter in Modbus Map
Table 8.18
1)
Value written in Modbus RTU telegram must be one or less than
register number. E.g. Read Modbus Register 1 by writing value 0 in
telegram.
8.8.9 How to Control the Frequency
Converter
This section describes codes which can be used in the
function and data fields of a Modbus RTU message.
8.8.10 Function Codes Supported by
Modbus RTU
Modbus RTU supports use of the following function codes
in the function field of a message.
Function
Function Code
Read coils
1 hex
Read holding registers
3 hex
Write single coil
5 hex
Write single register
6 hex
Write multiple coils
F hex
Write multiple registers
10 hex
Get comm. event counter
B hex
Report slave ID
11 hex
Table 8.19
Function
Function
Code
Sub-
function
code
Sub-function
Diagnostics 8
1
Restart communication
2
Return diagnostic register
10
Clear counters and
diagnostic register
11
Return bus message count
12
Return bus communi-
cation error count
13
Return bus exception error
count
14
Return slave message
count
Table 8.20
8.8.11 Modbus Exception Codes
For a full explanation of the structure of an exception code
response, refer to
8.8.5 Function Field
.
Code Name
Meaning
1
Illegal
function
The function code received in the query is
not an allowable action for the server (or
slave). This may be because the function
code is only applicable to newer devices,
and was not implemented in the unit
selected. It could also indicate that the
server (or slave) is in the wrong state to
process a request of this type, for
example because it is not configured and
is being asked to return register values.
RS-485 Installation and Set...
VLT
®
Micro Drive FC 51 Design Guide
80
MG02K202 - VLT
®
is a registered Danfoss trademark
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