VLT
®
5000/5000 Flux/6000 HVAC/8000 AQUA PROFIBUS
MG.90.D1.02 – VLT is a registered Danfoss trademark
5
Maximum total bus cable length
1 segment:
2 segments:
3 segments:
4 segments:
32 nodes
64 nodes
96 nodes
128 nodes
Transmission
(31 VLTs)
(1 repeater, 61 VLTs)
(2 repeater, 91 VLTs)
(3 repeater, 121 VLTs)
speed
[m]
[m]
[m]
[m]
9,6-187,5 kBaud
1000
2000
3000
4000
500 kBaud
400
800
1200
1600
1,5 MBaud
200
400
600
800
3-12 MBaud
100
200
300
400
■
Master-controlled drives
The PROFIBUS option card allows an enormous
flexibility of the control, diagnosis and parameteri-
zation of variable speed drives. The PROFIBUS
card behaves like a part of the VLT and enables
access to all parameters that are important for the
respective application. The variable speed drive
always acts as slave and is capable of exchanging
a multitude of commands and pieces of informa-
tion together with the master. Control signals such
as ”speed reference value”, ”start/stop” of the mo-
tor, ”reversion” are transmitted by the master in the
form of telegrams.
The
VLT
confirms the receipt by transmitting status
signals such as ”operation enabled”, ”reference
value reached”, ”motor stopped” etc. to the master.
The drive can also report errors and transmit alarm
and warning messages, e.g. ”
VLT error
” or ”excess
current”.
The PROFIBUS option card transmits signals in
accordance with the
PROFIBUS field bus standard,
EN 50170, part 3.
It can thus exchange data with all
masters that meet this standard; however, this
does not mean that all services available in the
PROFIBUS standard are supported. The
PROFIBUS
profile for variable speed drives
(version 2, PNO) is
a part of PROFIBUS which supports only those
services that concern applications with speed
control.
PROFIDRIVE is an implementation of the profile
developed by DANFOSS and several other firms.
Communications partner
The variable speed drive always acts as slave in a
control system and may thus exchange data with
one or more masters, depending on the type of the
application. The master may be a PLC or a PC with
a PROFIBUS communications
■
Cable lengths and number of nodes
The maximum cable length of a segment depends
on the transmission speed. The total cable length
includes stub lines, if applicable. A stub line is the
connection from the main bus cable to each node
if a ”T” connection exists instead of a direct con-
nection of the main bus cable to the nodes; cf. the
stub line length. The following table shows the
maximum permitted cable lengths and the maxi-
mum number of nodes or VLTs with 1, 2, 3 or 4 bus
segments.
Please note that a repeater switched between two
segments represents a node in both segments. The
number of VLTs is based on a system with only one
master. In the case of multiple masters, the num-
ber of VLTs must be reduced accordingly.
The total stub line length of a segment is limited as
follows:
Stub line length
Transmission
Max. stub line length
speed
per segment
[m]
9,6-93,75 kBaud
96
187,5 kBaud
75
500 kBaud
30
1,5 MBaud
10
3-12 MBaud
none
The PROFIBUS option car
d
