schmersal EX-CSS 180, Operating Instructions Manual

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5
EX-CSS 180
Operating instructions
Safety sensor
EN
4.4 Wiring example
Series-wiring of 4 safety sensors EX-CSS 8-180-2P+D+M-L-3G/D with common connecting cable for the inputs and outputs
The series-wiring of multiple sensors is realised by wiring in the control cabinet or in on-site junction boxes. A sensor of this type can also be used
as individual component or as first sensor of a chain. In these both cases, the positive operating voltage is supplied in both safety inputs.
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Safety-monitoring
module
CST-180-1
CST-180-1 CST-180-1
CST-180-1
EX-CSS 180 EX-CSS 180 EX-CSS 180 EX-CSS 180
4.5 Note on the total length of a safety sensor chain
Typical resistance of the different sensor connecting cables (20°C):
0,50 mm²: ca. 36 Ω / km
0,34 mm²: ca. 52 Ω / km
0,25 mm²: ca. 71 Ω / km
The resistance of the safety outputs / sensor used is load-dependent:
• 300 mΩ at 1 A current load, i.e. max. load of the safety outputs is
2 x 500 mA
• 30 mΩ at 100 mA current load, i.e. 2x 50 mA load when a safety-
monitoring module is connected.
• Power consumption of a safety sensor approx. 30 mA
• Diagnostic output of a safety sensor max. 50 mA
An approx. 200 m long sensor chain with 6 sensors, 0.5 mm² cable
section and at 20 °C, features approx. 2 V voltage drop when the total
current load of the safety outputs is 100 mA. If junction boxes are used
for longer cable lengths, the conductor sections between the junction
boxes should be designed so that the connected load causes a low as
possible voltage drop on the connection cables.
Protection is not required when pilot wires are laid. The cables however
must be separated from the supply and energy cables.
The max. fuse rate for a sensor chain depends on the section of the
connecting cable of the sensor.
For very long sensor chains, it can be useful supplying the
voltage at the beginning of the chain. In that case, the supply
of the safety sensors and that of the safety channels can be
protected individually e.g. by 1A gG each.