Bits no. 12-15 transfer parameter commands from master
to slave and return processed slave responses to the
master.
Bit no.
Parameter command
15
14
13
12
0
0
0
0
No command
0
0
0
1
Read parameter value
0
0
1
0
Write parameter value in RAM (word)
0
0
1
1
Write parameter value in RAM (double word)
1
1
0
1
Write parameter value in RAM and EEprom (double word)
1
1
1
0
Write parameter value in RAM and EEprom (word)
1
1
1
1
Read/write text
Table 7.5 Parameter commands master
⇒
slave
Bit no.
Response
15
14
13
12
0
0
0
0
No response
0
0
0
1
Parameter value transferred (word)
0
0
1
0
Parameter value transferred (double word)
0
1
1
1
Command cannot be performed
1
1
1
1
text transferred
Table 7.6 Response slave
⇒
master
If the command cannot be performed, the slave sends this
response:
0111 Command cannot be performed
- and issues the following fault report in the parameter
value (PWE):
PWE low
(Hex)
Fault Report
0
The parameter number used does not exit
1
There is no write access to the defined parameter
2
Data value exceeds the parameter's limits
3
The sub index used does not exit
4
The parameter is not the array type
5
The data type does not match the defined
parameter
11
Data change in the defined parameter is not
possible in the frequency converter's present
mode. Certain parameters can only be changed
when the motor is turned off
82
There is no bus access to the defined parameter
83
Data change is not possible because factory setup
is selected
Table 7.7
7.3.8 Parameter Number (PNU)
Bits no. 0-11 transfer parameter numbers. The function of
the relevant parameter is defined in the parameter
description in .
7.3.9 Index (IND)
The index is used together with the parameter number to
read/write-access parameters with an index, e.g.
15-30 Alarm Log: Error Code
. The index consists of 2 bytes,
a low byte and a high byte.
Only the low byte is used as an index.
7.3.10 Parameter Value (PWE)
The parameter value block consists of 2 words (4 bytes),
and the value depends on the defined command (AK). The
master prompts for a parameter value when the PWE block
contains no value. To change a parameter value (write),
write the new value in the PWE block and send from the
master to the slave.
When a slave responds to a parameter request (read
command), the present parameter value in the PWE block
is transferred and returned to the master. If a parameter
contains not a numerical value but several data options,
e.g.
0-01 Language
where [0] corresponds to English, and
[4] corresponds to Danish, select the data value by
entering the value in the PWE block. See Example -
Selecting a data value. Serial communication is only
capable of reading parameters containing data type 9 (text
string).
RS-485 Installation and Set...
VLT
®
Refrigeration Drive Design Guide
90
MG16G102 - VLT
®
is a registered Danfoss trademark
7
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