Danfoss VLT AutomationDrive FC 300 Design Manual page 132

FC 300 Design Guide
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).
The three types of telegram are:
Process block (PCD):
The PCD is made up of a data block of four bytes (2 words) and contains:
- Control word and reference value (from master to slave)
- Status word and present output frequency (from slave to master).
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.
Text block:
The text block is used to read or write texts via the data block.
The PKE Field
The PKE field contains two sub-fields: Parameter command and response AK, and Parameter number
PNU:
Bits no. 12-15 transfer parameter commands from master to slave and return processed slave responses
to the master.
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RS-485 Installation and Set-up
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