Series Connection - Pilz PSEN ml s 1.1 Operating Manual

Connection to control systems and evaluation devices
6.4

Series connection

Up to 16 safety switches can be configured in series.
In practice, the maximum possible number will be limited by the following parameters,
among others:
}
The required SIL level (e.g. SIL CL 3),
}
the required performance level (e.g. PL e (Cat. 4)),
} the maximum delay or risk time permitted by the application,
}
Cable length (see notes on cable lengths),
}
Height of supply voltage.
Ensure there is sufficient supply voltage, taking inrush currents and fusing into considera-
tion.
Notes on cable lengths
}
Determine the values under the following conditions:
Room temperature (25°C), conductor cross section 0.25 mm
(12, 22, Y32) each ≤ 10mA
[1]
L1
Legend
Operating Manual PSEN ml s 1.1/2.1/2.2
1004710-EN-05
CAUTION!
Extension of delay-on de-energisation
When several (n) devices are connected in series, the delay-on de-ener-
gisation time adds with the number of interconnected safety switches.
The max. delay-on de-energisation is made up of the
risk time (see Technical details [
+ (n-1) x max. delay-on de-energisation of the inputs
+ max. delay-on de-energisation of the evaluation device
[2]
[2]
L2 L3
[1] Safety control system
[2] Safety switch PSEN ml
73])
[2]
[2]
L4 L5
2
, output load per output
[2]
[2]
L6
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