Danfoss VLT AutomationVTDrive FC322 Design Manual page 156

Automation VT Drive FC322 Design Guide
Very long control cables and analog signals may in rare cases and depending on installation result in 50/60 Hz earth loops due to noise from mains supply
cables.
If this occurs, you may have to break the screen or insert a 100 nF capacitor between screen and chassis.
The digital and analog in- and outputs must be connected separately to the VLT Automation VT Drive common inputs (terminal 20, 55, 39) to avoid
ground currents from both groups to affect other groups. For example, switching on the digital input may disturb the analog input signal.
NB!
Control cables must be screened/armoured.
1. Use a clamp from the accessory bag to connect the screen to
the frequency converter de-coupling plate for control cables.
See section entitled Earthing of Screened/Armoured Control Cables
the correct termination of control cables.
5.3.14 Switches S201, S202, and S801
Switches S201 (A53) and S202 (A54) are used to select a current (0-20
mA) or a voltage (0 to 10 V) configuration of the analog input terminals
53 and 54 respectively.
Switch S801 (BUS TER.) can be used to enable termination on the RS-485
port (terminals 68 and 69).
Diagram showing all electrical terminals Electrical
See drawing in section
Installation.
Default setting:
S201 (A53) = OFF (voltage input)
MG.20.X1.22 - VLT
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5 How to Install
for
S202 (A54) = OFF (voltage input)
S801 (Bus termination) = OFF
NB!
It is recommended to only change switch position at power off.
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