VLT
®
8000 AQUA
Programming
Each transferred character begins with a start
bit. Subsequently, 8 data-bits are transferred,
corresponding to one byte. Each character is secured
via a parity bit set to "1" when there is even parity
(i.e. an even number of binary 1
’
s in the 8 data-bits
and the parity bit combined). A character ends with
a stop bite and thus consists of a total of 11 bits.
■
Telegram build-up under FC protocol
Each telegram begins with a start character (STX) =
02 Hex, followed by a byte that gives the telegram
length (LGE) and a byte that gives the VLT address
(ADR). Then follows a number of data bytes (variable,
depending on telegram type). The telegram ends
with a data control byte (BCC).
Telegram times
The speed of communication between a master and
a slave depends on the baud rate. The baud rate of
the AFD must be the same as the baud rate of the
master and is selected in parameter 502
Baudrate
.
After a reply telegram from the slave, there must be
a minimum pause of 2 characters (22 bits) before
the master is able to send another telegram. At a
baudrate of 9600 kbaud, there must be a minimum
pause of 2.3 msec. After the master has completed
the telegram, the response time of the slave back
to the master will be max. 20 msec. and there will
be a minimum pause of 2 characters.
Pause time, min.:
2 characters
Response time, min.:
2 characters
Response time, max.:
20 msec.
The time between individual characters in a telegram is
not to exceed 2 characters and the telegram must be
completed within 1.5 times the rated telegram time.
If the baudrate is 9600 kbaud and the telegram
length is 16 baud, the telegram must be
completed within 27.5 msec.
Telegram length (LGE)
Thetelegram length is the number of data bytes plus
address byte ADR plus data control byte BCC.
Telegrams with 4 data bytes have a length of:
LGE = 4 + 1 + 1 = 6 bytes
Telegrams with 12 data bytes have a length of:
LGE = 12 + 1 + 1 = 14 bytes
Telegrams that contain text have a length of 10+n
bytes. 10 is the fixed characters, while
’
n
’
is variable
(depending on the length of the text).
AFD address (ADR)
Two different address formats are used, in
which the address range of the AFD is either
from 1-31 or from 1-126.
1. Address format 1-31
The byte for this address range has the following profile:
Bit 7 = 0 (address format 1-31 active)
Bit 6 is not used
Bit 5 = 1: Broadcast, address bits (0-4), not used
Bit 5 = 0: No Broadcast
Bit 0-4 = AFD address 1-31
MG.80.A7.22 - VLT is a registered Danfoss trademark
143
Rosewood STP ST42 General (Operation and Maintenance Manual - Part 4:
Section 6.3 Manufacturers Manuals 6.3.33 Danfoss VLT Aquadrive 8000) Vendor Manual
QP Id: VM207
Active: 03/09/2013
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