Triggering; Threshold Trigger; Trigger Hysteresis - Novatech Bitronics M87X Series Manual

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5.3 Triggering

Triggers can be configured in the 70 Series to initiate several different actions:

Waveform Recorders

Disturbance Recorders

Digital Outputs

Virtual Outputs

SOE Entries

Resetting of various measurements (Demands, Energy, etc.)

Up to 120 triggers can be specified, of the following types:

Any measurement can be used to trigger a Waveform Recorder or Disturbance Recorder,

or create an entry in the SOE log. Configuring multiple triggers will cause a logical "OR" to

be applied to the list of triggers. The trigger thresholds are defined by the 70 Series

Configurator.

The user specifies the measurement to use, the threshold value, the

arithmetic function of the trigger, and the hysteresis value.

If the measurement is an analog value (such as volts or amperes), the user may choose to

trigger on values greater than or less than the threshold. Additionally, the user may

choose a rate-of-change trigger greater than, less than, or equal to the threshold value.

Rate-of-change intervals are calculated over the interval since the measurement was last

updated.

5.3.1a Trigger Hysteresis

Hysteresis is used to prevent chattering of contacts or unintended repeat-triggering of

recorders when a measurement fluctuates near the value where the action is intended to

occur. Refer to the Hysteresis column on the Recorder Triggers page of the 70 Series

Configurator program (below). The hysteresis setting is used to make the trigger occur

and re-initialized at different values. In the example below, since 60.3 Hz - 0.1 = 60.2 Hz,

the action takes place when frequency exceeds 60.3 Hz and re-initializes below 60.2 Hz.

When hysteresis is set to zero (default) the action triggers and resets at the same value.

ML0021

August 15, 2018

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