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42 lines
2.6 KiB
HTML
42 lines
2.6 KiB
HTML
<script type="text/html" data-help-name="rbe">
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<p>Report by Exception (RBE) node - only passes on data if the payload has changed.
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It can also block unless, or ignore if the value changes by a specified amount (Dead- and Narrowband mode).</p>
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<h3>Inputs</h3>
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<dl class="message-properties">
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<dt>payload
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<span class="property-type">number | string | (object)</span>
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</dt>
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<dd>RBE mode will accept numbers, strings, and simple objects.
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Other modes must provide a parseable number.</dd>
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<dt class="optional">topic <span class="property-type">string</span>
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</dt>
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<dd>if specified the function will work on a per topic basis. This property can be set by configuration.</dd>
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<dt class="optional">reset<span class="property-type">any</span></dt>
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<dd>if set clears the stored value for the specified msg.topic, or
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all topics if msg.topic is not specified.</dd>
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</dl>
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<h3>Outputs</h3>
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<dl class="message-properties">
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<dt>payload
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<span class="property-type">as per input</span>
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</dt>
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<dd>If triggered the output will be the same as the input.</dd>
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</dl>
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<h3>Details</h3>
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<p>In RBE mode this node will block until the <code>msg.payload</code>,
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(or selected property) value is different to the previous one.
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If required it can ignore the intial value, so as not to send anything at start.</p>
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<p>The <a href="https://en.wikipedia.org/wiki/Deadband" target="_blank">Deadband</a> modes will block the incoming value
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<i>unless</i> its change is greater or greater-equal than ± the band gap away from a previous value.</p>
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<p>The Narrowband modes will block the incoming value,
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<i>if</i> its change is greater or greater-equal than ± the band gap away from the previous value.
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It is useful for ignoring outliers from a faulty sensor for example.</p>
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<p>Both in Deadband and Narrowband modes the incoming value must contain a parseable number and
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both also supports % - only sends if/unless the input differs by more than x% of the original value.</p>
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<p>Both Deadband and Narrowband allow comparison against either the previous valid output value, thus
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ignoring any values out of range, or the previous input value, which resets the set point, thus allowing
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gradual drift (deadband), or a step change (narrowband).</p>
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<p><b>Note:</b> This works on a per <code>msg.topic</code> basis, though this can be changed to another property if desired.
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This means that a single rbe node can handle multiple different topics at the same time.</p>
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</script>
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