April 2004
10-6 Diagnosis and Troubleshootin g
Displaying Diagnostic Parameters
As part of its measurement menu, the PT878GC offers a list of
diagnostic parameters to aid in troubleshooting in the event of
flowcell, transducer, or electrical problems. You can select any
diagnostic parameter for display as a measurement as discussed
in Chapter 6 on pages 6-7 and 6-8. Table 10-2 below shows all
the available diagnostic parameters and ranges.
Table 10-2: Diagnostic Parameters
Diagnostic
Parameter Displays Good Bad
∆T Displays Delta T, or the differ-
ence between the upstream
and downstream transit times.
N/A Continuous
large fluctu-
ations of 1
micro sec-
ond or
more.
Amplitude Up Displays the value for the
amplitude discriminator of the
upstream transducer.
20-28 <20 or > 28.
Amplitude
Down Displays the value for the
amplitude discriminator of the
downstream transduce r.
20-28
fluctua-
tions
< 20 or > 28
fluctuations
T Up Displays the upstream transit
time of the ultrasonic signal in
micro seconds.
N/A N/A
T Down Displays the downstream tran-
sit time of the ultrasonic signal
in micro seconds.
N/A N/A
Gain/Up Displays upstream gain in dB. N/A N/A
Gain/Dn Displays downstream gain in
dB. N/A N/A
CNT up Displays the AGC DAC count
for upstream gain setting. N.A. N.A.
CNTdn Displ ays the AGC DAC count
for downstream gain setting. N.A. N.A.
Soundspeed
(m/s or f/s) Displays the measured sound
speed of the fluid. Check the sound speed
of fluid in Sound Speeds
and Pipe Size Data.