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UMG 96-PA / UMG 96-PA-MID / UMG 96-PA-MID+
Fig.
Shielding design for cabinet entry.
Cable
Strain relief
Braided shielding
of the cable
Grounding clamp
Noiseless ground
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
ensure a large surface area with good conduc-
tivity.
·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.
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 (3936 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.
8.4 Termination resistors
At the beginning and end of a segment, the cable
is to be terminated with resistors (120 Ω, 1/4 W).
Right
Wrong
Terminal strip in the switchboard cab-
inet.
Device with RS-485 interface.
(Without termination resistor)
Device with RS-485 interface.
(With termination resistor on the de-
vice)
NOTE
The device does not contain an integrated termina-
tion resistor!