1 reset signal requirements – Banner SC22-3E Safety Controller with Ethernet User Manual
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area unnoticed (a "pass-through hazard"). See section
4.5.3 Perimeter Guarding and Pass-Through Hazards
on page 35 for more in-
formaton.
WARNING: . . . Reset Switch Location
All reset switches must be accessible only from outside, and in full view of, the hazardous area. Reset switches
must also be out of reach from within the safeguarded space, and must be protected against unauthorized or inad-
vertent operation (e.g., through the use of rings or guards). If any areas are not visible from the reset switch(es), additional
means of safeguarding must be provided. Failure to do so could result in serious bodily injury or death.
Resetting a safeguard must not initiate hazardous motion. Safe work procedures require a start-up procedure to be followed and the
individual performing the reset to verify that the entire hazardous area is clear of all personnel, before each reset of the safeguard is
performed. If any area can not be observed from the reset switch location, additional supplemental safeguarding must be used: at a
minimum, visual and audible warnings of machine start-up.
4.5.1 Reset Signal Requirements
Both manual (latch) reset and system reset signals can be configured for monitored or non-monitored operation, as follows:
Monitored resets—Requires the reset signal to transition from low (0V dc) to high (24V dc) and then back to low. The high state duration
must be 0.3 to 2 seconds. This is said to be a “trailing edge trip event.”
Non-monitored resets—Requires only that the reset signal transitions from low (0V dc) to high (24V dc) and stays high for at least 0.3
seconds. After the reset, the reset signal can be either high or low. This is said to be a “leading-edge trip event.”
4.5.2 Automatic and Manual Reset Inputs Mapped to the Same Safety Output
Safety input devices can be configured for either manual (Latch mode) or automatic (Trip mode) reset and both types can be mapped to
the same Safety Output. In order for a Safety Output to turn ON, all associated safety input devices must be in their Run state. If one or
more of these safety input devices is configured for manual reset and one or more of them change from the Stop state to the Run state,
then the output will need a valid manual reset signal before it will turn ON.
If two safety inputs, each configured for manual reset, are mapped to the same Safety Output, then only one valid reset operation is
required to reset the Safety Output. A manual reset operation is valid when all safety inputs mapped to the Safety Output are in the Run
state and the manual reset is performed. If a manual reset is performed before a safety input is in the Run state, the manual reset signal
is ignored (except in the case of a two-hand control and an ON/OFF input).
7.5 System Resets and Lockout Conditions
on page 74 for more information about
resets.
Safety Device 1
(Auto)
Safety Device 2
(Manual)
Manual Monitored
Reset Input
Safety Output
Figure 15. Timing logic: auto and manual monitored reset safety inputs mapped to the same Safety Output (no delay)
SC22-3/-3E Safety Controller Instruction Manual
34
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