Danfoss VLT 8000 AQUA series User Manual

VLT
®
8000 AQUA
Programming
■ Serial communication for FC protocol
■ Protocols
As standard, all VLT 8000 AQUA units have a RS 485
port which enables a choice among four protocols.
• FC
• Profibus*
• Modbus RTU*
• DeviceNet*
• LonWorks*
*Pleasenotethattheseareoptioncardswith
separate input terminals.
■ Telegram communication
C
ontrol and reply telegrams
The telegram communication in a master/slave system
is controlled by the master. A maximum of 31 slaves
can be connected to one master, unless a re
peater
is used. If a repeater is used, a maximum of 126
slaves can be connected to one master.
The master continuously sends telegrams addressed
to the slaves and awaits reply telegr
ams from these.
Theresponsetimeoftheslavesismax.50ms.
Only a slave that has received a faultless
telegram addressed to that slave will response
by sending a reply telegram.
B
roadcast
A master can send the same telegram at the same
time to all slaves connected to the bus. In such
broadcast communicatio
n, the slave does not send
a reply telegram to the master, provided the telegram
has been correctly received. Broadcast communication
is set up in the address
format (ADR), see the next
page. Contents of a character (byte)
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) =
02Hex,followedbyabytethatgivesthetelegram
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 th
e baud rate. The
baud rate of the frequency converter must be
the same as the baud rate of the master and is
selected in parame
ter 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.
MG.83.A2.02 - VLT is a registered Danfoss trademark
149

Danfoss VLT 8000 AQUA series Specifications

General

Brand	Danfoss
Model	VLT 8000 AQUA series
Category	DC Drives
Language	English