P/N 133487
27
Banner Engineering Corp.
•
Minneapolis, U .S .A .
www .bannerengineering .com • Tel: 763 .544 .3164
SC22-3 Safety Controller
Instruction Manual
System Installation
3.6.2 Safety Outputs
The SC22-3 Safety Controller has three pairs of solid-state
safety outputs (SO1 a and b, SO2 a and b, and SO3 a and b) .
Each pair consists of two output signal switching devices
(OSSDs; see Figure 3-12) . The solid-state safety outputs are
actively monitored to detect short circuits to the supply voltage,
to each other, and to other sources of electrical energy . If a
failure is detected, the outputs will switch to an Off state . For
circuits requiring the highest level of safety and reliability, either
OSSD must be capable of stopping the motion of the guarded
machine controlled by a safety output, in an emergency .
OSSD Output Connections
The output signal switching device (OSSD) outputs must be
connected to the machine control such that the machine’s safety
related control system interrupts the circuit or power to the
machine primary control element(s) (MPCE), resulting in a non-
hazardous condition .
Final switching devices (FSDs) typically accomplish this when
the safety outputs go to the OFF state . See Figure 3-12 .
Refer to the output specifications (Section 2 .2) and Warning
below before making OSSD connections and interfacing the
Controller to the machine .
ON-Delays and OFF-Delays
Each safety output can be configured to function with either an
ON-delay or an OFF-delay (see Figure 3-11), where the output
turns ON or OFF only after the time limit has elapsed . An output
cannot have both ON- and OFF-delays . The ON and OFF time
delay limit options are from 100 milliseconds to 5 minutes, in
100 millisecond increments .
Current operation is to honor the OFF-delay for internal and
system faults, whenever possible .
CAUTION . . .
OFF-Delays
A safety output OFF-delay time will be honored even
if the safety input that caused the OFF-delay timer to
start switches back to the Run state before the delay time expires .
However, in cases of a power interruption or a power loss, an OFF-
delay time can end immediately .
If such an immediate machine
stop condition could cause a potential danger, then additional
safeguarding measures must be taken to prevent injuries.
Safety Input
SO1
SO2
(OFF-Delay)
500 ms
500 ms
Delay
Delay
Figure 3-11. Safety output with OFF-delay timing logic
NOTICE: Safety Outputs are Dual-Channel.
An individual safety output is not, by itself, capable of
meeting Category 4 applications (per ISO13849-1) . When
the risk assessment or relevant regulations require high
levels of safety integrity (i .e ., Category 4), both the output
signal switching device (OSSD) outputs must be connected
to the machine control so that the machine’s safety related
control system interrupts the circuit or power to the machine
primary control element(s) (MPCEs), resulting in a non-
hazardous condition .
Final switching devices (FSDs) typically accomplish this
when the OSSDs go to an OFF state . See Figures 3-12
to 3-15 .
WARNING . . .
Interfacing of Both
OSSDs
Both of the OSSD (Output Signal Switching
Device) outputs must be connected to the machine control
so that the machine’s safety-related control system interrupts the
circuit to the machine primary control element(s), resulting in a non-
hazardous condition .
Never wire an intermediate device(s) (e.g., PLC, PES, or PC)
that can fail in such a manner that there is the loss of the
safety stop command, OR in such a manner that the safety
function can be suspended, overridden, or defeated, unless
accomplished with the same or greater degree of safety.
WARNING . . .
Safety Output Lead
Resistance
In order to ensure proper operation, the
resistance in the safety output wires should not exceed
10 ohms. A higher resistance than 10 ohms may mask a short
between the dual-channel safety outputs and could create an
unsafe condition that may lead to serious bodily injury or death .
