Yokogawa digitalYEWFLO (DY) - Manual (Page 99)

IM 1F2B4-01-YIA
Page 94
TROUBLESHOOTING
Qf (Flowrate) U
k
= U
k
(m 3 )
U
k
= U
k
(acf)
•Liquid
Qf (Flowrate)
U
k
= U
k
(m 3 )
U
k
= U
k
(acf)
M (Mass flowrate) U
k
= p
f
* U(kg)
U
k
= 7.481 x
ρ
f
* U(lb) (7.481 is a conversion factor of USgal into acf)
6.4 S
IGNAL
C
ONDITIONING
6.4.1 YEWFLO Style “E” signal adjustment procedure
The YEWFLO Style “E” vortex flowmeter is a powerful, microprocessor-based instrument whose
noise discrimination functions have been factory-set for optimum performance based on customer
supplied application information. For most applications, these factory settings are ideal and should not
require adjustment by the user. However, difficult applications which generate a noisy output signal
may require fine tuning of these functions in an effort to better discriminate signal from noise.
There are five parameters associated with these functions: noise balance, TLA, low-cut frequency,
high-cut frequency and noise judge. This procedure will direct the user in the application of these
functions based on installation specific symptoms. One or more of these adjustments should correct
most of the problems that may be experienced. If problems persist, please contact our Technical
Assistance Center (TAC) 800-524-7378.
6.4.2 Problem solving
The type of problems that can be solved using this adjustment procedure include:
• Output occurrence with no flow
• Unstable output at low flow
• High output for a known flow rate
• High output (beyond programmed span)
Before making any adjustments, we recommend exploring other potential reasons and possible
solutions for these problems by checking your piping.
6.4.3 Piping checkout procedure
Many noise problems can be solved by some simple changes to the overall piping design. Make the
following checks:
• Make sure there is sufficient straight run upstream and downstream. For further
recommendations, refer "Piping Requirements".
• Check the installation for excessive vibration - 1g max for gas applications and 2g max for
liquid applications. If excessive vibration exists and the pipe is not braced, install
appropriate bracing to dampen the vibration. High vibration piping may require remote
mounting of the amplifier to reduce the amplitude of any transmitted vibration to the
shedder bar. It also may be desirable to mount the meter so the shedder bar is perpendicular