Terminals - Siemens SINAMICS S120 System Manual

5.12

Terminals

26.5 V hydraulic power supply
The 26.5 V voltage for the shutoff valve and valve electronics is supplied from an external
source connected via the HLA module. The HLA module monitors this voltage source. When
the HLA module identifies that the 26.5 V hydraulic power supply is not available, or does not
maintain the permitted limits, then r0046.7 is set to = 1 ("26.5 V power supply missing"). This
prevents the drive control from being commissioned.
● Failure of the 26.5 V supply during operation
The power is disabled and status bit "Velocity controller enable" canceled.
● The 26.5 V power supply returns – or when the 26.5 V power supply is switched on for
the first time
The power is not enabled until the power enable delay set in (p0231) has expired.
In the event of sudden failure (e.g. broken cable) of the external 26.5 V supply, the energy
storage capacitor for each axis on the HLA module provides energy to supply the servo
solenoid valve until such time as the pressure supply for a configured shutoff valve is
switched off. Note the following boundary conditions when selecting the valves:
● The energy content of the storage capacitors is dependent on:
– The tolerances of the capacitors
– The voltage level of the external supply
– The charging time of the integrated capacitors (instant of voltage failure)
● The available response time is mainly defined by:
– The power required for the actual machining step
– The response time of the shutoff valves
– The shutdown voltage threshold of the servo solenoid valves
Danger to life when the external 26.5 V power supply fails
A failure of the external power supply when the energy content of the storage capacitors is
too low can cause the shutoff valves to remain open. This can lead to critical situations that
may result in death or serious injury.
• The machine manufacturer must verify the interaction between valves, making
Hydraulic Drive
System Manual, 04/2015, 6SL3097-4BA00-0BP1
WARNING
allowance for all tolerances in the controlled system.
Drive functions
5.12 Terminals
187