MG.90.D1.02 – VLT is a registered Danfoss trademark
8
VLT
®
5000/5000 Flux/6000 HVAC/8000 AQUA PROFIBUS
■ LEDs
There are four LEDs on the PROFIBUS option
card:
LD1 and LD4: Flickering (very rapid blinking),
when data are being exchanged
through the option card.
Comment: with each ”flicker” of
the LEDs, the VLT is receiving a
telegram.
LD2 and LD3: Shining, when the option card is
initialized and ready for the data
exchange, or when data are alrea-
dy being exchanged.
Blinking, when the function for the
automatic baud rate determina-
tion attempts to determine the
current baud rate.
Note: a faulty connection of the
data line may also cause blinking
of the LEDs. (see “Physical con-
nection”).
It is important to terminate the bus line correctly.
Mismatches of the impedance may lead to reflec-
tions in the line and cause incorrect transmissions.
– The PROFIBUS option card is equipped with a
suitable termination which can be activated by
the switches 1 and 2 at the switch block S1
directly to the right above the terminal block
MK 1B. The bus termination is active when the
switch is in the ”ON” position.
The switches must never be set in oppo-
site directions. Both switches must be set
to ON or OFF.
– Most masters and repeaters are equipped with
their own termination.
– If an internal termination circuit in the form of
three resistors is connected to the bus line, a
5 V direct voltage must be used. Attention:
please make sure that it is voltaically separated
from the power supply cable.
The PROFIBUS option card
The PROFIBUS option card
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