5707070-A Troubleshooting and Customer Support 3-9
Sono-Trak™ Doppler Ultrasonic Flow Meter
Additional Troubleshooting Information
ECHO LED LIGHT CONSIDERATIONS
Sono-Trak™ Doppler ultrasonic flow meters require suspended solids or air bubbles
to operate. The strict requirement is that sonic discontinuities exist. If the speed of
sound in the solids and liquids are identical, then there are no sonic discontinuities
(which act as ultrasonic reflectors), and most Doppler flow meters will not function.
Some bacterial slurries and chemical slurries may have suspended solids but cannot be
measured with a Doppler flow meter for this reason.
The behavior of the Echo light on the display panel of your Doppler flow meter
electronics enclosure may provide indication as to whether the Doppler flow meter is
the correct one for your application. If after troubleshooting your unit, the Echo light
does not remain on steady while you are operating your unit, you may need to
consider changing the meter to a transit time meter.
See “Determining if Your Process/Installation is Right for a Doppler Flow Meter” on
page 2-3 and “Troubleshooting the Unit” on page 3-1 if you are having trouble
maintaining a steady Echo light during operation of your flow meter.
Table 3-6. Echo light scenarios
Echo light
condition
Flow rate
reading
Applicable Meter Solution
Illuminated
steady
Yes Doppler flow meter If the Echo light is on and the
flow reading appears correct,
the Doppler is the best meter
for your application.
Flashing Yes Doppler flow meter
or
Transit time meter
There may be an inadequate
level of reflective materials in
the flow to ensure correct flow
readings. Move the transducers
until you get a steady light, or
replace your Doppler meter
with a transit time meter.
Off Yes Transit time meter There may be an inadequate
level of reflective materials in
the flow to ensure correct flow
readings. Replace your Doppler
meter with a transit time meter.
Off No flow Contact Factory Clamp on transducers may not
be able to provide accurate
flow readings in your
application.
