Rockwell Automation 442L SC300 Safety Sensor User Manual - Manual (Page 14)

12 Rockwell Automation Publication 10000202762 Ver 00 - January 2012
Chapter 3 Product description
Reset
If you activate the restart interlock on the SC300 (internal) and also realize a restart
interlock on the machine (external), then each restart interlock gets its own button.
When actuating the reset button (for the internal restart interlock) …
• The SC300 activates the output signal switching devices.
• Switches the SC300 to green.
Only the external restart interlock guards against the machine from restarting. After
pressing the reset button for the SC300, the operator must also press the restart button
for the machine. If the reset button and the restart button are not pressed in the specified
sequence, the dangerous state must remain disrupted.
Recommendation The reset button guards against the accidental and inadvertent operation of the external
restart button. The operator must first acknowledge the safe state with the reset button.
The electrical connection of the reset button is described in the “Electrical Installation”
section on page 27. The configuration of the internal restart interlock is described on
page 42.
External device monitoring (EDM)
The SC300 has external device monitoring. If you activate the external device
monitoring, then the SC300 checks whether the contactors are actually de-energized
when the protective device triggers. If, after an attempted Reset/restart, the EDM does
not detect a response from the switched device within 300 ms, the EDM will deactivate
the output signal switching devices again. In this case the safety camera system signals as
follows:
• The system remains at red. The status LED illuminates.
• The status LED flashes with a short duty cycle
• The diagnostics LED 2 flashes with a short duty cycle.
Note If the system is unable to change to a safe operational state (e.g. after contactor failure),
the system locks and shuts down completely (“lock­out,” see page 45). The electrical
connection for the external device monitoring is described in the “Connecting the
SC300” section on page 28. The configuration of the external device monitoring is
described in the “Configuration” chapter on page 40.