24
P/N 133487
Banner Engineering Corp.
•
Minneapolis, U .S .A .
www .bannerengineering .com • Tel: 763 .544 .3164
SC22-3 Safety Controller
Instruction Manual
System Installation
• Mute on Power-Up Enabled. When the Mute on Power-Up
option is enabled, the Controller will go into a mute cycle if
the conditions for a valid mute cycle are fulfilled at power-up .
Specific valid mute signal conditions must be present for a
mute cycle to be initiated and maintained .
If Auto Power-Up is configured, the Controller allows
approximately 2 seconds for the input devices to become
active (closed) to accommodate systems that may not be
immediately active at power-up .
If Manual Power-Up is configured and all other conditions are
satisfied, the first valid system reset after the muted safety
inputs are active (Run state or closed) will result in a mute
cycle .
The Mute On Power-up function should only be used if safety
can be assured when the mute cycle is expected, and the
utilization of this function is the result of a risk assessment
and is required by that particular machine operation .
WARNING . . .
Mute and Bypass
Mute and Bypass operations must be done in a
way that minimizes personnel risk. The following
rules and methods must be implemented when creating mute and
bypass applications:
• Guard against unintended stop signal suspension by using one or
more diverse-redundant mute sensor pairs or a dual channel key-
secured bypass switch .
• Set reasonable (no longer than needed) mute and bypass function
time limits .
WARNING . . .
Use of Mute and
Bypass Functions
Failure to follow these rules could lead to an
unsafe condition that could result in serious injury or death.
Refer to Sections A .10 and A .11 for more information .
Mute
Enable
ON or OFF
Safety
Input
Mute Sensor
Pair
Safety
Output
Figure 3-5. Timing diagram for one mute sensor pair with mute
enable
3.5.5 Bypass Function
The safety device bypass is a manually activated and temporary
suspension of one or more safety input stop signals when no
immediate hazard is present . Bypass switches can be mapped
to one or more of the following safety input devices:
• Safety gate (interlocking) switches
• Optical sensors
• Two-hand control devices
• Safety mats
• Protective stop
When the bypass switch signal changes to the Bypass (Run)
state, it will turn ON or keep ON all the safety outputs that are
controlled by the bypassed safety input devices only if all other
non-bypassed safety devices that are mapped to these safety
outputs are in the Run state .
Bypass Time Limit. A bypass function time limit can be
established to limit how long the safety input device bypass
is active . The time limit can be adjusted from 1 second to 30
minutes and cannot be disabled . Only one time limit can be set,
and this limit will apply to all safety devices that are bypassed .
At the end of the time limit, safety output control authority is
handed back to the bypassed safety input devices .
Bypass with Mute. If a mute sensor is mapped to the safety
input device and the safety input device is in the STOP state, at
least one of the Mute sensors must be in the Mute (Run) state in
order to start a new bypass cycle . If the conditions are right for
bypass, the mute status output indicator (if configured) will start
flashing at 1 Hz .
Light
Screen
Mute
Sensor 1 (2)
Mute
Sensor 2 (1)
Bypass
Switch
Safety
Output
Bypass Time Expired
Bypass Time Expired
Don’t Care
Figure 3-7. Light screen with mute sensors and bypass switch
timing logic
