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
7.4.8 Parameter Number (PNU)
Bits no. 0-11 transfer parameter numbers. The function of the relevant parameter is defined in the parameter description in the Programming Guide.
7.4.9 Index (IND)
The index is used together with the parameter number to read/write-access parameters with an index, e.g. par. 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.
7.4.10 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. par. 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).
Par. 15-40
FC Type
to par. 15-53
Power Card Serial Number
contain data type 9.
For example, read the unit size and mains voltage range in par. 15-40
FC Type
. When a text string is transferred (read), the length of the telegram is
variable, and the texts are of different lengths. The telegram length is defined in the second byte of the telegram, LGE. When using text transfer the
index character indicates whether it is a read or a write command.
To read a text via the PWE block, set the parameter command (AK) to ’F’ Hex. The index character high-byte must be “4”.
Some parameters contain text that can be written to via the serial bus. To write a text via the PWE block, set the parameter command (AK) to ’F’ Hex.
The index characters high-byte must be “5”.
7 RS-485 Installation and Set-up
VLT HVAC Low Harmonic Drive Operating In-
structions
156 MG.16.A1.02 - VLT
®
is a registered Danfoss trademark
7
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