57 / 157V3.3 11.07.2007 KRC-AD-KRC2ed05-BA en
4. Safety
4.3 Safety features
4.3.1 Overview of the safety features
The following table indicates the operating modes in which the safety features 
are active.
4.3.2 ESC safety logic
The ESC (Electronic Safety Circuit) safety logic is a dual-channel computer-
aided safety system. It permanently monitors all connected safety-relevant 
components. In the event of a fault or interruption in the safety circuit, the pow-
er supply to the drives is shut off, thus bringing the robot system to a standstill.
The ESC safety logic monitors the following inputs:
 Local EMERGENCY STOP
 External EMERGENCY STOP
 Operator safety
 Enabling
 Drives OFF
 Drives ON
 Operating modes
 Qualifying inputs
4.3.3 Operator safety input
The operator safety input is used for interlocking fixed guards. Safety equip-
ment, such as safety gates, can be connected to the dual-channel input. If 
nothing is connected to this input, operation in Automatic mode is not possible. 
Operator safety is not active for test modes T1 and T2. 
Safety features T1 T2 AUT AUT EXT
Operator safety -
- active active
Emergency Stop button
(STOP 0)
active active - -
Emergency Stop button
(STOP 1)
- - active active
Enabling switch active
active - -
Reduced velocity
active - - -
Jog mode
active active - -
Software limit switches active
active active active
Danger!
In the absence of functional safety equipment, the robot can cause personal 
injury or material damage. No safety equipment may be dismantled or deac-
tivated while the robot is in operation.
Further information is contained in the robot controller operating instructions.