Burkert 178 354, Operating Instructions Manual

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8.3.6 cut (cut off) - Zero point cut-off
In order to guarantee leak-tight closing of the valve, the valve is completely
de-energised with input signals below the set limit (0.1 to 5.0 % of the set
standard signal) when the zero point shutdown is active.
In addition to its control function, the valve can also take on the function of a
cut-off valve.
Illustration 8-10: Cut (Cut off) - Zero point cut-off
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With a set value of 0.0 %, the zero point cut-off is deactivated. Even
at an input signal of 0 %, the valve no longer reliably shuts off the flow.
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The valve flow control restarts with a hysteresis of 0.5 %.
The reactivation of the current controle starts as soon as the input
signal is set to a value 0.5 % above the defined threshold value; i. e.
there is a hysteresis of 0.5 % for the activation and deactivation of the
cut off function.
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The range of the input signal lying below the set threshold is no longer
available for the current control and fluidic flow control.
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