The parameter assignments of the function block are defined by the determination of the maximum gain rate as well as the ymax and ymin thresholds for the Y output. The maximum velocity rate indicates the maximum by which the output may change within one second.
The amount will be evaluated by the rate parameter.
If rate = 0 is configured, then the Y output follows the X input immediately (Y=X).
The limits ymax and ymin limit the output within the prescribed range. Therefore ymin ≤ Y ≤ ymax.
The outputs qmax and qmin indicate that the output has reached a limit or that the output signal has been capped.
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qmax = 1 if Y ≥ ymax
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qmin = 1 if Y ≤ ymin
There are three operating modes, which are selected via the inputs MAN and HALT:
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Operating mode
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MAN
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HALT
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Meaning
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Automatic
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0
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0
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The current value for Y is constantly calculated and displayed.
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Manual mode
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1
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0 or 1
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The manual value YMAN will be transmitted fixed to the output Y. The control output is, however, limited by ymax and ymin.
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Halt
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0
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1
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The output Y will be held at the last value. The output will no longer be changed, but can be overwritten by the user.
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Illustration of the dynamic behavior of the VLIM function block.
The function block follows the jump to input X with maximum change in speed (rate). Output Y remains at a standstill in Halt mode, in order to subsequently move on from the position at which it has stopped. It is also clear to see the limits of output Y durch ymax and ymin with the relevant messages qmax and qmin.
