Application examples for conventional PSRclassic safety relays
102597_en_03
PHOENIX CONTACT
5.4
Enable switch
An additional manually actuated device that is used together with a startup control, and that
permits machine operation when continuously actuated. Enable devices are frequently used
together with emergency stop devices for the temporary suspension of safety functions.
Simply pressing an enable switch must not start machine operation (see EN 60204-1). The
hazardous movement should only be triggered by activating an additional control device.
Enable devices with the following properties should be selected:
–
Designed according to ergonomic principles
a) For a type with two position settings:
–
Position 1: off function of the switch (actuator is not operated)
–
Position 2: enable function (actuator is operated)
a) For a type with three position settings:
–
Position 1: off function of the switch (actuator is not operated)
–
Position 2: enable function (actuator is operated and in its mid position)
–
Position 3: off function (actuator is operated past its mid position)
–
Returning from position 3 to position 2 does not activate the enable function.
Summary of Contents for 2702924
Page 137: ......
