Danfoss VLT Micro Drive FC 51 - The Data Field

8.4.4 Frequency Converter Address (ADR)
Address format 1-126
Bit 7=1 (address format 1-126 active)
Bit 0-6=frequency converter address 1-126
Bit 0-6=0 Broadcast
The slave returns the address byte unchanged to the
master in the response telegram.
8.4.5 Data Control Byte (BCC)
The checksum is calculated as an XOR-function. Before the
first byte in the telegram is received, the Calculated
Checksum is 0.
8.4.6 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).
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)
ADRLGESTX PCD1 PCD2 BCC
130BA269.10
Illustration 8.6
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.
PKE INDADRLGESTX PCD1 PCD2 BCC
130BA271.10
PWE
high
PWE
low
Illustration 8.7
Text block
The text block is used to read or write texts via the data
block.
PKE IND
130BA270.10
ADRLGESTX PCD1 PCD2 BCCCh1 Ch2 Chn
Illustration 8.8
RS-485 Installation and Set...
VLT
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Micro Drive FC 51 Design Guide
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