Function description
Operating Manual PSSu E F 4DO 0.5(-T)(-R)
21316-EN-08
14
Output test
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Outputs that are switched on are checked via regular off tests.
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Test pulses for outputs that are switched on: see Technical details"
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Outputs that are switched on are switched off for the duration of the test pulse.
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The load must not switch off because of the test.
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Outputs that are switched off are checked via regular on tests.
–
Test pulses for outputs that are switched off: see Technical details"
–
Outputs that are switched off are switched on for the duration of the test pulse.
–
The load must not switch on because of the test.
Excluding individual outputs from the output test:
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If a plant is particularly sensitive to the test pulses, they may be switched off for indi-
vidual outputs.
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The test must be replaced by other measures, depending on the safety requirement.
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When test pulses are switched off:
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The correct switch status is always checked.
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The output's ability to switch will not be detected until the next time the output is
switched on/off.
Testing for shorts
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A test is regularly carried out to check for shorts between the outputs.
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For applications in accordance with Category 4, PL e and SIL 3, detection of shorts
between contacts must be guaranteed either via the on/off test or through other meas-
ures (e.g. asynchronous switching). A short between contacts must be simulated during
commissioning.
WARNING!
When wiring an output with capacitance it is essential to note the pulse dur-
ation, repetition period and scan time of the power-up test, otherwise the
load may switch on unintentionally.
