Danfoss VLT Midi Drive FC 280 Programming Manual page 10

Introduction
1 1
In rare cases, long control cables and analog signals could
result in 50/60 Hz ground loops due to noise from mains
supply cables. If this occurs, break the screen or insert a
100 nF capacitor between screen and chassis.
The digital and analog inputs and outputs must be
connected separately to the common inputs (terminal 55)
of the frequency converter to avoid ground currents from
both groups to affect other groups. For example, switching
on the digital input could disturb the analog input signal.
Input polarity of control terminals
12 13
Illustration 1.3 PNP (Source)
12 13
Illustration 1.4 NPN (Sink)
NOTICE
Control cables must be shielded/armoured.
8
VLT
PNP (Source)
Digital input wiring
18 19 27 29 32 33
NPN (Sink)
Digital input wiring
18 19 27 29 32 33
Danfoss A/S © 12/2015 All rights reserved.
®
Midi Drive FC 280
See the section Using Shielded Control Cables in the design
guide for the correct termination of control cables.
55
Illustration 1.5 Grounding of Shielded/Armoured Control
Cables
1.3.2 Start/Stop
Terminal 18 = parameter 5-10 Terminal 18 Digital Input [8]
Start.
Terminal 27 = parameter 5-12 Terminal 27 Digital Input [0]
55
No operation (Default coast inverse).
Speed
Start/Stop
[18]
Illustration 1.6 Start/Stop
12 13 18 19 27 29 32 33
Start/Stop
MG07C102