General Description of Functions
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EN-US · 30.30.01.02084 · 02 · 12/20
An absolute air consumption measurement can be made only using a pressure value supplied
externally via IO-Link.
The measured value for the absolute air consumption (air consumption per cycle) is reset at the start of
suction and then continuously updated during the cycle. It can continue to change until after the end of
blow-off.
Energy consumption measurement:
The ejector determines the electrical energy consumed during a suction cycle, including the energy it con-
sumes itself and the energy consumed by the valve coils.
To determine the values for the air consumption as a percentage and the electrical energy consumption,
the neutral phase of the suction cycle must also be taken into account. Therefore, the measured values
can only ever be updated when the next suction cycle begins. Throughout the cycle, the measured values
displayed then represent the results from the previous cycle.
7.25.3 Predictive Maintenance (PM)
For early detection of wear and other impairments to the vacuum gripper system, the ejector features
functions for detecting trends in the quality and performance of the system. The leakage and dynamic
pressure are measured for this purpose.
Measurement of leakage:
The leakage (represented as the vacuum drop per time unit in mbar/s) after the control function inter-
rupts suction because the vacuum limit value H1 has been reached is measured.
The measured value for the leakage rate and the related quality assessment in percent are reset at the
start of every suction cycle and constantly updated during the cycle as moving averages. The values there-
fore remain stable until after the suction cycle is complete.
Measurement of dynamic pressure:
This measures the system vacuum achieved during unobstructed suction. The duration of the measure-
ment is approx. 1 second. Therefore, to evaluate a valid dynamic pressure, uninterrupted suction is re-
quired for at least 1 second after starting the suction, i.e. the suction point must not be covered by a part.
Measured values below 5 mbar or above the vacuum limit value H1 are not regarded as valid dynamic
pressure measurements and are rejected. The result of the last valid measurement is retained. Measured
values that are higher than the vacuum limit value (H2-h2) and simultaneously lower than vacuum limit
value H1 result in a condition monitoring event.
The dynamic pressure (vacuum during unobstructed suction) and the related performance assessment in
percent are initially unknown when the ejector is switched on. As soon as a dynamic pressure measure-
ment can be performed, they are updated and retain their values until the next dynamic pressure mea-
surement.
Quality assessment:
To evaluate the overall gripping system, the ejector calculates a quality rating based on the measured sys-
tem leakage. The greater the leakage in the system, the worse the quality rating of the gripping system.
Conversely, low leakage results in a high quality rating.
Performance calculation:
Similar to the quality assessment, the performance calculation is used to evaluate the system status. The
performance of the gripping system can be assessed based on the determined dynamic pressure. Opti-
mally configured gripping systems lead to low dynamic pressure and thus to high performance. Con-
versely, poorly configured systems result in low performance. Dynamic pressure events that exceed the
vacuum limit value (H2-h2) always result in a performance rating of 0%. A dynamic pressure value of
0 mbar (indicator that a valid measurement was not obtained) also results in a performance rating of 0%.