Danfoss VLT HVAC Basic Drive FC 101 Design Manual page 81

RS-485 Installation and Set...
STX LGE
Illustration 7.5
Parameter block
The parameter block is used to transfer parameters
between master and slave. The data block is made up of
12 bytes (6 words) and also contains the process block.
STX LGE
Illustration 7.6
7 7
Text block
The text block is used to read or write texts via the data
block.
STX LGE
Illustration 7.7
7.4.7 The PKE Field
The PKE field contains two subfields: Parameter command
and response (AK) and Parameter number (PNU):
AK
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Illustration 7.8
Bits no. 12-15 transfer parameter commands from master
to slave and return processed slave responses to the
master.
80
VLT
ADR PCD1
ADR PKE IND
ADR PKE IND
PKE IND PWE
high
PNU
MG18C402 - VLT
®
HVAC Basic Drive Design Guide
PWE PWE
high low
Ch1 Ch2 Chn
Parameter commands master ⇒ slave
Bit no.
15 14
0 0
0 0
0 0
PWE
low
0 0
1 1
1 1
1 1
Table 7.5
Response slave ⇒master
Bit no.
15 14
0 0
0 0
0 0
0 1
1 1
Table 7.6
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is a registered Danfoss trademark
PCD2
PCD1 PCD2
PCD1 PCD2
Parameter command
13 12
0 0 No command
0 1 Read parameter value
1 0 Write parameter value in RAM (word)
1 1 Write parameter value in RAM (double
word)
0 1 Write parameter value in RAM and
EEprom (double word)
1 0 Write parameter value in RAM and
EEprom (word)
1 1 Read text
Response
13 12
0 0 No response
0 1 Parameter value transferred (word)
1 0 Parameter value transferred (double
word)
1 1 Command cannot be performed
1 1 text transferred
BCC
BCC
BCC