SmartSwarm 300 Series
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82
10.2.4 HIGH THRESHOL D
Trigger when the enriched register value increases above a fixed threshold.
This event is only applicable to Input Registers and Holding Registers, not Discrete Inputs and Coils.
It is applicable to numeric data types only. It is not applicable to a counter. A counter is a rollover data type and so
we have no record of its true accumulated value on which to base the threshold.
Inputs,
Coils
Input Registers,
Holding Registers
ENUM
Numeric
STRING
COUNTER
High Threshold
✔
Table 30. High Threshold Event
When you select the High Threshold event type on a register, you must enter two fields:
●
The
Threshold
field specifies the value above which the register must increase in order to trigger an
MQTT publish.
●
The
Hysteresis
field allows you to prevent multiple MQTT publishes due to process noise. Once the
register has crossed the Threshold value in the positive (increasing) direction, it must cross the value
[Threshold - Hysteresis] in the negative direction before it is considered to have re-crossed.
NOTE: This rule is significantly different from the previous rules discussed above, because it is STATEFUL.
For example, when the High Threshold is crossed in either direction an MQTT publish will be triggered.
But if the register remains above (or below) the threshold no further messages will be published. An
MQTT publish will occur only on state transitions.
