SafeShield Safety Light Curtain Hardware User Manual
11
Restart Interlock
Figure 7: Schematic layout of the protective operation
The dangerous state of the machine (1) is interrupted if the light
path is broken (2), and is not re-enabled (3) until the operator
presses the reset button.
Notes Do not confuse the restart interlock with the starting
interlock on the machine. The start interlock prevents the
machine starting at power up. The restart interlock
prevents the machine starting again after an error or an
interruption in the light path.
The restart interlock can be implemented in two different ways:
• With the internal restart interlock of the SafeShield safety light
curtain: The SafeShield safety light curtain controls the restart.
• With the restart interlock of the machine (external): The
SafeShield safety light curtain has no control over the restart.
The possible combinations are shown in the following table:
Table 4: Permissible configuration of the restart interlock
Restart
interlock of
SafeShield
Restart
interlock of
the Machine Permissible Application
Deactivated Deactivated Only if one cannot stand between the
light curtain and the machine. Observe
EN 60_204-1!
Deactivated Activated All
Activated Deactivated Only if one cannot stand between the
light curtain and the machine. Observe
EN 60_204-1!
Activated Activated All. Restart interlock of the SafeShield
safety light curtain handles the reset
function (see “Reset” below).
The electrical connection of the reset button is described in the
“Reset Button” section on page 28.
Device symbol SafeShield safety light curtain Host
(receiver), context menu Configuration draft, Edit, file card
General, option Restart interlock.
Recommendation
You can indicate the status “Reset required” using a signal lamp.
The SafeShield safety light curtain has a dedicated output for this
purpose. The electrical connection of the signal lamp is described
in “Connection of a Signal Lamp to the Output Reset Required” on
page 28.
Notes You can define whether the operator must press the reset
button, or press and release it to start the function. If you
configure Press, then the reset is performed before the
operator releases the reset button again. This can be
useful if you want, for example, to use a two-hand control
unit also as the reset button for the safety light curtain.
Device symbol SafeShield safety light curtain Host
(receiver), context menu Configuration draft, Edit, file card
General, option Reset button active.
Reset
If you want to activate the restart interlock on the SafeShield safety
light curtain (internal) and also a restart interlock on the machine
(external), then each restart interlock has its own button.
When actuating the reset button (for the internal restart
interlock) …
• The SafeShield safety light curtain activates the switching outputs.
• The SafeShield safety light curtain changes to green.
ATTENTION: Always configure the
application with restart interlock!
Ensure that there is always a restart
interlock. The SafeShield safety light curtain
is unable to verify if the restart interlock of
the machine is operable. If you deactivate
both the internal and the machine’s restart
interlock, the operators of the machine will
be at an acute risk of injury.
!
ATTENTION: Never configure Reset
after press if it is possible to stand
behind the light curtain!
Reason: If pressing the reset button (without
releasing it) is sufficient as the reset signal,
then the safety light curtain cannot
differentiate the operation of the reset
button from a short-circuit to 24V. In case of
a short-circuit, the light curtain would be
inadvertently reset. In this case the operator
would be in serious danger.
!
