3.2.4.3 Control Terminal Functions
Frequency converter functions are commanded by
receiving control input signals.
•
Each terminal must be programmed for the
function it will be supporting in the parameters
associated with that terminal. SeeTable 3.4 for
terminals and associated parameters.
•
It is important to confirm that the control
terminal is programmed for the correct function.
See 4 User Interface and Programming for details
on accessing parameters and for details on
programming.
•
The default terminal programming is intended to
initiate frequency converter functioning in a
typical operational mode.
3.2.4.4
Using Screened Control Cables
Correct screening
The preferred method in most cases is to secure control
and serial communication cables with screening clamps
provided at both ends to ensure best possible high
frequency cable contact.
If the earth potential between the frequency converter and
the PLC is different, electric noise may occur that will
disturb the entire system. Solve this problem by fitting an
equalizing cable next to the control cable. Minimum cable
cross section: 16 mm
2
.
Illustration 3.7
1
Min. 16 mm
2
2 Equalizing cable
Table 3.5
50/60Hz ground loops
With very long control cables, ground loops may occur. To
eliminate ground loops, connect one end of the screen-to-
ground with a 100nF capacitor (keeping leads short).
Illustration 3.8
Avoid EMC noise on serial communication
This terminal is connected to earth via an internal RC link.
Use twisted-pair cables to reduce interference between
conductors. The recommended method is shown below:
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