OnRobot HEX-E QC User Manual page 111

OPERATION
NOTE:
In order to help the Auto-level part to function, make sure to use the same
suction caps for A and B channels and set the arms to be symmetrical.
When any of the VG grippers is used without a HEX-E/H QC but used on an E-series controller
the following extra option becomes available:
Seek: when checked, the same seeking action will happen as above. Since the auto leveling
part is not used the VG grippers need to be parallel to the surface.
NOTE:
Setting a lower vacuum gives a faster grip with less wear on the vacuum cups.
It also reduces the risk of leaving suction marks on delicate workpieces.
It can take a few seconds when pressing Play or Test before the robot program
starts. This is normal.
When the two channels are set to different vacuum percentages the VG
grippers automatically release air into the channel with lower pressure. This
feature is activated when the pressure is more than 20% vacuum over the
setting. Releasing air generates a characteristic rumbling sound and change in
pumping speed.
VG Release
This command is used to release the grip of the workpiece by removing vacuum.
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