Siemens SINAMICS S120 Manual page 317

Terminals X21.1 and X21.2
Note
Wiring to a digital input of the Control Unit
Output terminal X21.1 must be wired to a digital input on the CU. The drives supplied with
power from the Smart Line Module have to use this signal as a ready signal. This ensures
that a pulse enable can only be issued for the drives (motor or generator operation) when the
infeed is ready.
If interconnection with a digital input on the CU is not possible, the signal must be evaluated
by a higher-level control system instead. It is not permissible that the control system sets the
drives to ready until the infeed "Ready" signal is present.
Note
Evaluating the "Prewarning" signal
The "Prewarning" signal at output terminal X21.2 warns against an overload. If this signal is
set to low, the control system shuts the drives down before the "Ready" signal switches to
low. If the "Ready" signal switches to "low", the drive pulses must be suppressed within
4 ms.
Note
The Smart Line Module signals "Ready" (X21.1 = "High"), even if one of the line conductor
voltages is not available. In this case, regenerative feedback is deactivated and an alarm is
output at X21.2 (DO, Warning I
If regenerative feedback was deactivated by applying a "high" signal to terminal X22.2 (DI,
Disable), no alarm will be output at X21.2 (DO, Warning I
Terminals X21.3 and X21.4
For operation, the 24 V DC voltage must be connected to terminal X21.3 and ground to
terminal X21.4.
Pulse cancellation is activated if the power supply is disconnected. As a consequence,
regenerative feedback is deactivated and the bypass relay drops out. If the Line Module is
not disconnected from the line supply when the EP terminal is de-energized, for example,
because a line contactor is not installed, then the DC link remains charged.
NOTICE
Damage to the drive electronics when switching the line contactor under load
When switching the line contactor (type according to the recommended selection) under
load, then the contacts will be subject to premature wear. This can cause the contactor to
malfunction, with subsequent damage to the drive electronics.
• Use a leading opening auxiliary contact or use a Voltage Sensing Module (VSM10).
• If this is not possible, then avoid switching the line contactor under load.
Booksize Power Units
Manual, (GH2), 07/2016, 6SL3097-4AC00-0BP8
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