Siemens SINAMICS G120 Operating Instructions Manual page 113

NOTICE
Overvoltages for long signal cables
Using long cables at the inverter's digital inputs and 24 V power supply can lead to overvoltage
during switching operations. Overvoltages can damage the inverter.
● If you use cables of more than 30 m at the digital inputs and 24 V power supply, connect
Note
Malfunction caused by incorrect switching states as the result of diagnostic flows in the off
state (logical state "0")
In contrast to mechanical switching contacts, e.g. emergency stop switches, diagnostic flows
can also flow with semiconductor switches in the off state. If interconnection with digital inputs
is faulty, the diagnostic flows can lead to incorrect switching states and thus to a malfunction
of the drive.
● Observe the conditions for digital inputs and digital outputs specified in the relevant
manufacturers documentation.
● Check the conditions of the digital inputs and digital outputs in regard to the flows in off
state. If applicable, connect the digital inputs with suitably dimensioned, external resistors
to protect against the reference potential of the digital inputs.
Table 4-18
Solid or finely stranded
Wiring the terminal strip in compliance with EMC
● If you use shielded cables, then you must connect the shield to the mounting plate of the
control cabinet or with the shield support of the inverter through a good electrical connection
and a large surface area.
Further information is provided on the Internet:
60612658)
● Use the shield connection kit (Article No. 6SL3264-1EA00-0LA0) of the Control Unit as
strain relief.
Converter with the CU250S-2 Control Units
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG
an overvoltage protection element between the terminal and the associated reference
potential.
We recommend using the Weidmüller overvoltage protection terminal with designation
MCZ OVP TAZ DIODE 24VDC.
Permissible cables and wiring options
Finely stranded conduc‐
conductor tor with non-insulated
conductor end sleeve
EMC installation guideline
4.5 Connecting the interfaces for the inverter control
Finely stranded conduc‐
tor with partially insula‐
ted conductor end
sleeve
(http://support.automation.siemens.com/WW/view/en/
Installing
Two finely stranded con‐
ductors with the same
cross-section with parti‐
ally insulated twin end
sleeves
111