Data Character (Byte) - Danfoss VLT 8000 AQUA series Operating Instructions Manual

Data character (byte)

The build-up of data blocks depends on the type of
telegram. There are three types of telegram and the
telegram type applies to both control telegram (master
⇒ slave) and reply telegram (slave ⇒ master). The
three types of telegram are the following:
1. Parameter block, used for transferring parameters
between master and slave. The data block has 12
bytes (6 words) and also contains the process block.
2. Process block, built up as a data block with
four bytes (2 words), covering:
- Control word and reference value (from
master to slave)
- Status word and present output frequency
(from slave to master).
3. Text block, used for reading or writing texts
via the data block.
MG.83.A2.02 - VLT is a registered Danfoss trademark
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VLT 8000 AQUA
1. Parameter bytes
Parameter commands and replies (AK) Bits
no. 12-15 are used for transferring parameter
commands from master to slave and the slave's
processed reply back to the master.
Parameter commands → master slave:
Bit no.
15 14 13 12 Parameter command
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
Reply slave→ master:
Bit no.
15 14 13 12 Reply
0 0 0 0 No reply
0 0 0 1 Parameter value transferred
(word)
0 0 1 0 Parameter value transferred
(double word)
0 1 1 1 Command cannot be executed
1 1 1 1 Text transferred
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