Manual

PNOZ s4
Operating Manual PNOZ s4
21396-EN-12
4
Safety features
The relay meets the following safety requirements:
} The circuit is redundant with built-in self-monitoring.
} The safety function remains effective in the case of a component failure.
} The correct opening and closing of the safety function relays is tested automatically in
each on-off cycle.
} The unit has an electronic fuse.
Block diagram/terminal configuration
InputInput
A1 A2 S21 S22

Power
Reset/
Start
S34
S11 S12

Y32

K1
K2
13
23 33
24 34
14
41
42
Interface
expansion
unit



Rotary cam arrangement monitoring Front view with cover, right: Front view without cover
Grey highlighted area: Applies only with U
B
= 48 – 240 V AC/DC
*Insulation between the non-marked area and the relay contacts: Basic insulation (overvolt-
age category III), safe separation (overvoltage category II)
Function description
}

Single-channel operation: no redundancy in the input circuit, earth faults in the start
circuit and input circuit are detected.
} Dual-channel operation without detection of shorts across contacts: redundant input cir-
cuit, detects
– earth faults in the start and input circuit,
– short circuits in the input circuit and, with a monitored start, in the start circuit too.
}

Dual-channel operation with detection of shorts across contacts: redundant input cir-
cuit, detects
– earth faults in the start and input circuit,
– short circuits in the input circuit and, with a monitored start, in the start circuit too,
– shorts between contacts in the input circuit.