node-red-nodes/function/rbe/locales/en-US/rbe.html

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