SL1188P Ultrasonic transit-time flowmeter
Revision
：
2.0.0
Page 50 of 81
7.3.
Frequently Asked Questions and Answers
Question: New pipe, high quality material, and all installation requirements met: why still no signal detected?
Answer: Check pipe parameter settings, installation method and wiring connections. Confirm if the coupling
compound is applied adequately, the pipe is full of liquid, transducer spacing agrees with the screen
readings and the transducers are installed in the right direction.
Question: Old pipe with heavy scale inside, no signal or poor signal detected: how can it be resolved?
Answer: Check if the pipe is full of fluid. Try the Z method for transducer installation (If the pipe is too close to
a wall, or it is necessary to install the transducers on a vertical or inclined pipe with flow upwards
instead of on a horizontal pipe).
Carefully select a good pipe section and fully clean it, apply a wide band of coupling compound on
each transducer face (bottom) and install the transducer properly.
Slowly and slightly move each transducer with respect to each other around the installation point until
the maximum signal is detected. Be careful that the new installation location is free of scale inside the
pipe and that the pipe is concentric (not distorted) so that the sound waves do not bounce outside of the
proposed area.
For pipe with thick scale inside or outside, try to clean the scale off, if it is accessible from the inside.
(Note: Sometimes this method might not work and sound wave transmission is not possible because of
the a layer of scale between the transducers and pipe inside wall).
Question: Why is there no CL (current loop) output?
Answer: Check if the desired current output mode is set in Window M55. See if the CL is powered off by
“
CL
Off
”
settings.
Open the electronics enclosure to inspect the hardware circuit. Check to see if the short-circuit terminal
near terminal 3 is in place, i.e. Direct Output Mode(set CL output as Transmitter Mode with external
power supply).
Question: Why is the CL output abnormal?
Answer: Check to see if the desired current output mode is set in Window M55.
Check to see if the maximum and minimum current values are set properly in Windows M56 and M57.
Re-calibrate CL and verify it in Window M49.
Question: Why is the flow rate still displayed as zero while there is fluid obviously inside the pipe and a symbol
of
“
R
”
displayed on the screen?
Answer: Check to see if
“
Set Zero
”
was carried out with fluid flowing inside the pipe(Refer to Window M42). If
it is confirmed, recover the factory default in Window M43.
Question: With a poor measurement site environment in the plant and the voltage and power supplies fluctuating
widely, is the instrument really able to keep running 24 hours a day repeatedly without stopping and
last for several years under such conditions?
Answer: Flowmeter is designed to work with high reliability under such conditions. It is provided with an
intelligent signal conditioning circuit and internal correction circuitry. It will work under strong
interference conditions and is able to adjust itself with strong or weak sound waves. It will work in a
wide band of voltage: 90-245VAC or 10V~36VDC voltage.
