The Data Field; The Pke Field - Danfoss VLT FC 360 Design Manual

RS-485 Installation and Set...

3.4.6 The Data Field

The structure of data blocks depends on the type of telegram. There are three telegram types, and the type applies for both
control telegrams (master⇒slave) and response telegrams (slave⇒master).
3 3
The 3 types of telegram are:
Process block (PCD)
The PCD is made up of a data block of 4 bytes (2 words) and contains:
- Control word and reference value (from master to slave)
- Status word and present output frequency (from slave to master)
STX LGE
Illustration 3.4 Process Block
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 3.5 Parameter Block
Text block
The text block is used to read or write texts via the data block.
STX LGE
Illustration 3.6 Text Block

3.4.7 The PKE Field

The PKE field contains two subfields: Parameter command
and response (AK) and Parameter number (PNU):
44
®
VLT
ADR PCD1
ADR PKE IND
ADR PKE IND Ch1
MG06B202 - VLT
AutomationDrive FC 360 Design Guide
PWE PWE
high low
Ch2 Chn
AK
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Illustration 3.7 PKE Field
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PCD2
PCD1 PCD2
PCD1 PCD2
PKE IND PWE
high
PNU
BCC
BCC
BCC
PWE
low