5 General Description of Functions
EN-US · 30.30.00.00422 · 08 · 09/22
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5 General Description of Functions
5.1 Applying Suction to the Workpiece/Part
The ejector is designed for handling and holding workpieces by means of a vacuum in combination with
suction systems. The vacuum is generated in a nozzle according to the venturi principle, using suction
generated by the flow of accelerated compressed air. Compressed air is channeled into the ejector and
flows through the nozzle. A vacuum is generated immediately downstream of the motive nozzle; this
causes the air to be sucked through the vacuum connection. The air and compressed air that have been
removed by the suction exit together via the silencer.
The venturi nozzle on the ejector is activated and deactivated using the suction command:
•
In the variant NO (normally open), the venturi nozzle is deactivated when
the suction signal is received.
•
In the NC (normally closed) variant, the venturi nozzle is activated when the
suction signal is received.
The ejector has an integrated air saving function and automatically regulates the vacuum in suction
mode:
•
The electronics switch the venturi nozzle off as soon as the set vacuum limit
value (switching point H1) is reached.
•
When objects with airtight surfaces are picked up, the integrated non-re-
turn valve prevents the vacuum from dropping.
•
If the system vacuum drops below the limit value switching point H1-h1 due
to leaks, the venturi nozzle is switched back on.
•
Depending on the vacuum, the H2 process data bit is set once a workpiece is
picked up safely. This enables the further handling process.
If small volumes are to be evacuated, the set switching point H1 may be exceeded consider-
ably before the vacuum is switched off. This system behavior does not constitute an error.
5.2 Depositing the Workpiece/Part (Blowing Off)
In blow off mode, the vacuum circuit of the ejector is supplied with compressed air. This ensures that the
vacuum drops quickly, allowing the workpiece to be deposited quickly.
The ejector provides two blow off modes for selection:
•
Externally controlled blow off:
The “blow off” valve is controlled directly by
the “blow off” signal input. The ejector switches to blow off mode for as
long as the signal is present.
•
Internally time-controlled blow off:
The “blow off” valve is automatically
activated for the configured time period as soon as the ejector leaves “suc-
tion” mode. This function makes it possible to save an output on the con-
troller.
4
The internal time-controlled blow off is activated by setting a value greater than zero for the blow
off time.
The ejector also has a manual mode. In this mode, the ejector can be controlled using the
buttons on the ejector’s foil keypad. See the “Manual mode” section for more details.
