Danfoss VLT 5000 Series Design Guide

The length of telegrams containing texts is 10+n bytes.
10 represents the fixed characters, while the 'n' is var-
iable (depending on the length of the text).
Frequency converter address (ADR)
Two different address formats are used, with the fre-
quency converter's address range being either 1-31 or
1-126.
1. Address format 1-31
The byte for address range 1-31 has the following pro-
file:
Bit 7 = 0 (address format 1-31 active)
Bit 6 is not used
Bit 5 = 1: Broadcast, address bits (0-4) are
not used
Bit 5 = 0: No Broadcast
Bit 0-4 = Frequency converter address 1-31
2. Address format 1-126
The byte for address range 1 - 126 has the following
profile:
Bit 7 = 1 (address format 1-126 active)
Bit 0-6 = Frequency converter address 1-126
Bit 0-6 = 0 Broadcast
The slave sends the address byte back unchanged in
the response telegram to the master.
Example:
writing to frequency converter address 22 (16H) with
address format 1-31:
Data control byte (BCC)
The data control byte is explained in this example:
Before the first byte in the telegram is received, the
Calculated CheckSum (BCS) is 0.
When
the first byte (02H) has been received:
BCS = BCC EXOR “first byte”
(EXOR = exclusive-or)
BCS = 0 0 0 0 0 0 0 0 (00 H)
EXOR
1. byte
= 0 0 0 0 0 0 1 0 (02H)
BCC = 0 0 0 0 0 0 1 0 (02H)
Each subsequent byte gates with BCS EXOR and pro-
duces a new BCC, e.g.:
BCS = 0 0 0 0 0 0 1 0 (02H)
EXOR
2nd byte
= 1 1 0 1 0 1 1 0 (D6H)
BCC = 1 1 0 1 0 1 0 0 (D4H)
Data Character (byte)
The structure of data blocks depends on the type of
telegram. There are three types of telegram, and the
type of telegram applies for both control telegrams
(masterslave) and response telegrams (slavemaster).
The three types of telegram are:
-
Parameter block, used to transfer parame-
ters between master and slave. The data
block is made up of 12 bytes (6 words) and
also contains the process block.
-
The process block is made up of a data block
of four bytes (2 words) and contains:
-
Control word and reference value
-
Status word and present output fre-
quency (from slave to master)
-
Text block, which is used to read or write texts
via the data block.
VLT
®
5000 Design Guide
MG.52.B2.02 - VLT
®
is a registered Danfoss trademark 85
Serial communication

Danfoss VLT 5000 Series Specifications

General

Brand	Danfoss
Model	VLT 5000 Series
Category	DC Drives
Language	English