PNOZ s3
Operating Manual PNOZ s3
21395-EN-10
4
Safety features
The relay meets the following safety requirements:
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The circuit is redundant with built-in self-monitoring.
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The safety function remains effective in the case of a component failure.
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The correct opening and closing of the safety function relays is tested automatically in
each on-off cycle.
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The unit has an electronic fuse.
Block diagram/terminal configuration
Input
Input
A1 A2
S21 S22
Power
Reset/
Start
S34
S11 S12
Y32
K1
K2
13 23
24
14
Interface expansion
unit
Centre: Front view with cover, right: Front view without cover
*Insulation between the non-marked area and the relay contacts: Basic insulation (overvolt-
age category III), safe separation (overvoltage category II)
Function description
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Single-channel operation: no redundancy in the input circuit, earth faults in the start
circuit and input circuit are detected.
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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.
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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.
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Automatic start: Unit is active once the input circuit has been closed.
