janitza UMG 512-Pro, User Manual And Technical Data

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UMG 512-PRO www.janitza.com
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8.2 RS-485 interface
The RS-485 interface of this device is designed
as a 3-pole plug contact and communicates using
the Modbus RTU protocol.
The cables used must be suitable for an ambient
temperature of at least 80°C.
Recommended cable type:
·Unitronic Li2YCY(TP) 2x2x0.22 (Lapp cable)
Fig. RS-485 connection example
A B
RS-485 bus
Data GND
WARNING
Risk of injury due to electrical voltage!
The Profibus, RS-485, temperature measurement
input and residual current measurement input are
not galvanically isolated from each other.
It is therefore essential to note that dangerous
voltages at these inputs can have an effect on
the respective other connections.
8.2.1 Termination resistors
At the beginning and end of a segment, the cable
must be terminated with resistors (120 Ω, 1/4 W).
Termination within the device is possible via DIP
switch S1 of the device.
Right
Wrong
Terminal strip in the switchboard cabinet.
Device with RS-485 interface.
(Without termination resistor)
Device with RS-485 interface.
(With termination resistor on the device)
S1
ON
OFF
Fig. Termination activated via DIP switch (ON).