the envelope threshold limit can be adjusted to exclude portions of the envelope, which may
be causing the Tn detection problem.
① Envelope Signal ④ Crossover Marker
② HiSet Envelope Threshold ⑤ TN Marker
③ LoSet Envelope Threshold ⑥ Zero Baseline
Figure 10-4 Envelope Threshold Adjustment
1. If it appears that the default placement of the Tn marker is incorrect or unstable, it can be
adjusted by pressing the <5> key on the keypad to invoke the [Hi Set #] command or by
pressing the <6> key to invoke the [Low Set #] command (while viewing the envelope
screen). A horizontal line representing the envelope threshold level will appear along with
a number indicating the percentage level. The High and Low thresholds can then be moved
either up or down on the envelope using the <+> or <-> keys. While viewing the Tn marker
position, adjust the thresholds so that they are well above the baseline "noise" level but
below the first major peak.
2. To exit this mode, press the <0> key.
Signal Masking Function: (Hot Key 7)
Under conditions of extremely low signal amplitude, a noise spike associated with the
flowmeter receive signal window may be present on the extreme left side of the graph display.
If this spike is large enough it may interfere with the signal detection routines.
1. To eliminate this noise from the signal processing routines, press the <7> key to invoke the
[Mask Set #] command, then press the <+> key until the noise is no longer present in the
receive waveform.
2. Press <0> to exit this command.
Troubleshooting
10.3 Test Facilities Graph Screen
FUP1010 IP67 Portable Flowmeter
126
Operating Instructions, 02/2010, A5E02951522A Revision 01
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