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Configuration
July 2016
Figure 2-14. Reranging the transmitter with LOI
VIEW CONFIG
SENSOR CONFIG
UNITS
RERANGE
RERANGE
LOOP TEST
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2.8.2
Damping
The damping function changes the response time of the transmitter to smooth variations in output
readings caused by rapid changes in input. Determine the appropriate damping setting based on the
necessary response time, signal stability, and other requirements of the loop dynamics of the system.
The default damping value is 5.0 seconds and can be reset to any value between 1 and 32 seconds.
The value chosen for damping affects the response time of the transmitter. When set to zero (disabled),
the damping function is off and the transmitter output reacts to changes in input as quickly as the
intermittent sensor algorithm allows. Increasing the damping value increases transmitter response time.
With damping enabled, if the temperature change is within 0.2% of the sensor limits, the transmitter
measures the change in input every 500 milliseconds (for a single sensor device) and outputs values
according to the following relationship:
At the value to which the damping time constant is set, the transmitter output is at 63% of the input
change and it continues to approach the input according to the damping equation above.
For example, as illustrated in
the sensor limits—from 100 degrees to 110 degrees, and the damping is set to 5.0 seconds, the
transmitter calculates and reports a new reading every 500 milliseconds using the damping equation. At
5.0 seconds, the transmitter outputs 106.3 degrees, or 63% of the input change, and the output
continues to approach the input curve according to the equation above.
For information regarding the damping function when the input change is greater than 0.2% of the
sensor limits, refer to
26
N P
–
Damped Value
=
P =previous damped value
N =new sensor value
T = damping time constant
U =update rate
Figure
"Intermittent sensor detection" on page
ENTER VALUES
ENTER VALUES
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2
T U
–
P
----------------- -
2
T U
2-15, if the temperature undergoes a step change—within 0.2% of
Reference Manual
00809-0100-4728, Rev MB
LRV
LRV
URV
URV
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33.
Configuration
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