Rs-485 Bus Connection; Bus Termination - Danfoss vlt FC 102 Operating Instructions Manual

5. How to operate the frequency converter
NB!
An active HAND-OFF-AUTO signal via the digital inputs has higher priority than the control keys [Hand on] [Auto on].
[Reset]
is used for resetting the frequency converter after an alarm (trip). The key can be

5.1.4. RS-485 Bus Connection

One or more frequency converters can be connected to a controller (or
master) using the RS-485 standard interface. Terminal 68 is connected
to the P signal (TX+, RX+), while terminal 69 is connected to the N signal
(TX-,RX-).
5
If more than one frequency converter is connected to a master, use par-
allel connections.
In order to avoid potential equalizing currents in the screen, earth the cable screen via terminal 61, which is connected to the frame via an RC-link.

Bus termination

The RS-485 bus must be terminated by a resistor network at both ends. If the drive is the first or the last device in the RS-485 loop, set the switch S801
on the control card for ON.
For more information, see the paragraph
58
Switches S201, S202, and S801
.
MG.11.A6.02 - VLT ® is a registered Danfoss trademark
®
VLT HVAC Drive Operating Instructions
Enabled Disabled
[1] or [0] via par. 0-43
Illustration 5.6: Connection example.
Reset Keys on LCP
.