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Reference Manual
00809-0100-4832, Rev AA
October 2004
3-17
Rosemount 3095FC
Figure 3-12. AI General Tab
Screen
AI Advanced Tab
The AI Advanced tab enables the user to configure features, such as filtering,
A/D conversions, and clipping for the selected Analog Input. Use the following
steps to configure the AI Advanced Tab.
See Figure 3-13 on page 3-18.
1. Select Device > I/O > AI Points > Advanced
2. Enter a Filter value, which is a weighted sample using a percentage
of the last value plus a percentage of the new value. The entered data
is the percentage of the last value used. The Filter is calculated every
Scan Period by the formula:
(Last Value × Entered %) + (New Value × (100 - Entered %)) = Filtered Value
3. Enter the Adjusted A/D 0%, which is the calibrated Analog-to-Digital
(A/D) reading that corresponds to 0%input. In the Calibrate function,
this value is altered to set the 0% input exactly at the Low Reading
EU value to eliminate transmitter and system errors.
4. Enter the Adjusted A/D 100%, which is the calibrated A/D reading
corresponding to 100% input. This value is used to convert the input
to engineering units. In the Calibrate function, this value is altered to
set the 100% input exactly at the High Reading EU value.
NOTE
Raw A/D Input displays the current reading directly from the analog-to-digital
converter. Actual Scan displays the actual amount of time in seconds that
passes between scans. This number should be the same as shown for the
Scan Period parameter if the system is not overloaded.
5. The Enable Average Raw Values calculates and averages the raw
readings during the Scan Period. Use the outcome as the Raw A/D
Input during calculations. For example: When Enabled, an Analog
Input point configured with a Scan Period of 1.0 seconds obtains a
new value from the A/D every 50 milliseconds. During the Scan
Period, 20 values are obtained from the A/D and summed together. At
EU Value calculation, the values summed are divided by the number
of samples taken during the scan period and are used as the Raw
A/D Input. Disable this function to acquire instantaneous values.