LAUREL LTE Series, Руководство пользователя

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• Alarm Type. Selections are Non-Latching and Latching. Under Non-Latching, the relay is only
closed (or open) while the Alarm State is Active. Under Latching, the activated relay remains
closed (or opens) until reset regardless of the Alarm State. Resetting is normally achieved by
temporarily grounding one of the transmitter’s control inputs, which has been set to Function
Reset under the “Input+Display” tab.
•
Alarms 1,2 No. Rdgs to Alarm. Selections are binary steps from 1 to 128. This is the number
of consecutive alarm readings that must occur to create an Active alarm. Numbers higher than
2 provide some Alarm filtering so that 1 or 2 noisy readings do not cause an Active Alarm. The
Alarm becomes Inactive if one of the consecutive readings fails to be an Alarm reading. The
Alarm readings counter then resets to 0.
17. INPUT SIGNAL FILTERING
The Filter tab provides selections to minimize the effect time jitter and electrical noise which
can affect trigger points. In most cases, filtering is only available for Item 1 and is grayed out
for totalizing and stopwatch functions.
• Time Constant provides a moving average filter with the following eight equivalent RC time
constants: no filter, 0.1 sec, 0.2 sec, 0.4 sec, 0.8 sec, 1.6 sec, 3.2 sec, and 6.4 sec. The longer
time constants provide superior noise filtering at the expense of fast response time. Note that
filtering can also be accomplished by lengthening the Gate time under the Input+Display tab.
• Type allows selection of Adaptive or Conventional filtering. With Adaptive, the time constant is
changed dynamically so that the transmitter can respond rapidly to actual changes in signal
while filtering out random noise. The moving average filter is reset to the latest reading when
the accumulated difference between individual readings and the filtered reading exceeds a
Threshold. The accumulated difference is also reset to zero when the latest reading has a
different polarity than the filtered reading. With Conventional filtering, the adaptive feature is
disabled and the Time Constant does not change.
• Threshold allows selection of Low Adaptive or High Adaptive for the Adaptive filter selection.
Normally select Low. Select High if the signal has large spurious transients which should not
be considered as an actual change in signal.
Peak/Valley Filter allows the peak (maximum) or valley (minimum) functions to be based on
Unfiltered or Filtered readings. Normally select Unfiltered. Select Filtered if you expect spurious
readings which you do not wish to capture.