Siemens SITRANS LUT400, Operating Instructions Manual

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Page 262 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS A5E33329501
mmm
mm
App. A - T
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cal Ref
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Measurement Response
Response Rate limits the maximum rate at which the display and output respond to
changes in the measurement. There are three preset options: slow, medium, and fast.
Once the real process fill/empty rate (m/min by default) is established, a response rate
can be selected that is slightly higher than the application rate. Response Rate
automatically adjusts the three rate parameters that affect the output response rate.
Damping
Damping Filter (2.2.3.) smooths out the response to a sudden change in level. This is an
exponential filter and the engineering unit is always in seconds.
In 5 time constants, the output rises exponentially: from 63.2% of the change in the first
time constant, to almost 100% of the change by the end of the 5th time constant.
Note: Units are defined in Quick Start (1.1.) and are in meters by default.
When Response
Rate set to:
Fill Rate per Minute (2.3.1.)/
Empty Rate per Minute (2.3.2.)
automatically adjust to: Damping Filter
(2.3.3.) automatically
adjusts to:
*
Slow 0.1 m/min 100.0 s
Medium 1.0 m/min 10.0 s
Fast 10.0 m/min 0.0 s
Note: Damping Filter can be set to 0 in order to display measurement readings as fast
as fill/empty rates permit. Fill Rate per Minute, and Empty Rate per Minute work in
conjunction with Damping Filter, therefore, if readings are slow to respond to changes,
check that Fill and Empty Rates are set to values greater than or equal to the desired
Response Rate.
Le
ve
l (m)
Time (s)
smoothed output input (level)
Damping example
time constant = 2 seconds
input (level) change = 2 m