Functional description
01.00 | Electric gripper EGP with safety functions | System description | en | 1381596
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4 Functional description
4.1 Definition of the safe state of the gripper
The safe state of the gripper is a state in which no danger to per-
son or machine arises from the gripper.
For the system setup, this means that there are the following two
safe states depending on the position of the gripper fingers:
• Safe state 1
–
Position of the gripper fingers is defined
The gripper maintains its position and gripping force to avoid
losing a workpiece that it may be holding.
• Safe state 2
–
Position of the gripper fingers is not defined
To avoid crushing, the power to the gripper is disconnected.
The change from safe state 1 to safe state 2 is made as soon as the
position of the gripper fingers is undefined.
This is the case, for example, when a gripped workpiece is re-
moved by force application from the gripper during monitored op-
eration, no release or the logical release signal low or Emergency
Stop. If a workpiece is removed, the gripper fingers move until a
signal change is made to one of the sensors (overrun traverse). If
the configured gripping force is very low, it is possible that the
gripper fingers maintain the position without an overrun.
The switch from safe state 2 to safe state 1 is is not allowed.
It is possible to exit safe state 1 by reenabling or confirming.
Exiting safe state 2 is only possible by solving and acknowledging
the existing fault and then reenabling. This prevents unwanted or
unexpected reactivation. Alternatively, agreeing and subsequent
confirmation can ensure that the gripper is powered until the con-
firmation button is released or cut off (panic function).
