janitza UMG 103-CBM User Manual

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35
8.2 RS-485 interface
e.g. connection
to the UMG 604
as a gateway (master)
e.g.
connection
of further
slave devices
RS-485 bus
A
B
A
B
B
A
C
Fig. Shielding design for cabinet entry.
Cable
Strain relief
Braided shielding
of the cable
Grounding clamp
Noiseless ground
WARNING
Transmission error and risk of injury due to
electrical fault!
Atmospheric discharge can cause transmission
errors and hazardous voltages on the device.
Therefore please abide by the following:
· Connect the shielding to functional earth
(PE) at least once.
· In the case of larger sources of interference,
frequency converters in the switchboard
cabinet, connect the shielding to functional
earth (PE) as close as possible to the device.
· Observe the maximum cable length of
1200 m (3960 ft.) at a baud rate of 38.4 k.
· Use shielded cables.
· Route interface cables spatially separated
or additionally insulated from mains volt-
age-carrying system components.
The RS-485 interface of this device is designed as
a 3-pole plug contact and communicates using the
Modbus RTU protocol.
Device address 1 and the baud rate are factory set
to "automatic detection".
120 Ω
Fig. RS-485 interface, 3-pole plug contact
RS-485 bus
A
B
B
A
C
Fig. RS-485 interface, 3-pole plug contact with termina-
tion resistor (part no. 52.00.008)
8.3 Shielding
Provide a twisted and shielded cable for connec-
tions via the interfaces and observe the following
points for shielding:
· Ground the shields of all cables leading into the
cabinet at the cabinet entrance.
· Connect the shield to a noiseless ground and en-
sure a large surface area with good conductivity.
· Do NOT connect the shield to terminal C (GND)
· Mechanically restrain the cables before the
grounding clamp to prevent damage from cable
movement.
· Use suitable cable glands, for example PG
glands, to lead the cable into the switchboard
cabinet.
Recommended cable type:
· Unitronic Li2YCY(TP) 2x2x0.22 (Lapp cable)
INFORMATION
CAT cables are not suitable for the bus wiring.
Use the recommended cable type for this pur-
pose.
Data GND C
Data GND C

janitza UMG 103-CBM Specifications

General

Brand	janitza
Model	UMG 103-CBM
Category	Measuring Instruments
Language	English