Cursor Use On The Spectra Graph; How To Use Spectra Graph Data And Controls - Siemens SITRANS F Operating Instructions Manual

Section 7
7.10

CURSOR USE ON THE SPECTRA GRAPH

CURSOR
High Limit Cursor
Low Limit Cursor
Noise Level Set Cursor
7.11

HOW TO USE SPECTRA GRAPH DATA AND CONTROLS

When you first access the Spectra Graph, the data shown on the top highlighted line shows Velocity in
feet-per-second (F/S) on the left side and the volumetric Flow Rate in the current rate units on the right
side. You can scroll the data shown using the <Up and Down> Arrows.
Pressing the <Up Arrow> changes the data in the highlight to [Diagnostic Data] containing, from left to
right: (Hz) Doppler shift frequency in Hertz, (mV) Signal Amplitude in millivolts, (FFT Pk) Peak FFT
magnitude and (%D) FFT Percent Deviation. Carefully inspect the data for Signal Amplitude and Per-
cent Deviation. Refer to the "Available Adjustments to Spectra Graph" table in paragraph 7.12 and the
"Reflexor Diagnostic Data" table found in paragraph 7.13. Press the <Down Arrow> to return to Veloc-
ity.
Press the <Down Arrow> from Flow Velocity in feet per second (F/S) to advance to the Noise Level Set
cursor control. A numeric indication of the Noise Level Cursor position is provided in the highlighted
area. Refer to the "Available Adjustments To Spectra Graph" table found in paragraph 7.12.
Adjust the Noise Level cursor, if required, by pressing the <+> key to increase or <-> key to decrease.
NOTE: A delay in response to all keys will occur. This is due to the longer periodic sampling of
the keyboard by the processor while performing FFT's.
Press the <Down Arrow> from Noise Level to advance to the High Limit cursor control. The <+> and
<-> key are active in this position. Refer to the "Available Adjustments To Spectra Graph" table found in
paragraph 7.12.
This cursor appears as a vertical line on the right side of the Spectra
Graph. All signals to the right of this line will be excluded from the flow
calculation. Use this adjustment if the right side of the Spectra Graph
has noise that is larger in amplitude than the signal that is produced by
flow. The cursor may be arbitrarily placed at two times the maximum
flow expected.
This cursor appears as a vertical line on the left side of the Spectra
Graph. All signals to the left of this line will be excluded from the flow
calculation. Use this adjustment if the left side of the Spectra Graph
has noise that is larger in amplitude than the signal that is produced by
flow. The cursor may be arbitrarily placed at one half the minimum flow
expected.
This cursor appears as a horizontal line on the Spectra Graph. All sig-
nals below this line will be excluded from the flow calculation. Position
the cursor approximately one quarter the height of the FFT peak.
7-6
USAGE TIPS
1010PFM-3G