User`s manual

Chapter 5 Troubleshooting & Repair AX2200/AX2300 Instruction Manual
5-10 CM2-AX2000-2001 (Rev. 4, 4/2014)
3. The meter may be reacting to actual changes in the flow
stream. The output can be smoothed using a time constant.
The displayed values can be smoothed using the time constant
in the Display Menu. The analog outputs can be smoothed
using the time constant in the Output Menu. A time constant
of 1 will result in the change in value reaching 63% of its final
value in one second. A time constant of 4 is 22%, 10 is 9.5%
and 50 is 1.9% of the final value in one second. The time
constant equation is shown below (TC = Time Constant).
4. The vortex coefficient Ck may be incorrectly set. The Ck is a
value in the equation used to determine if a frequency
represents a valid vortex signal given the fluid density and
signal amplitude. In practice, the Ck value controls the
adaptive filter, fi, setting. During flow, view the f and fi values
in the first level of the hidden diagnostics. The fi value should
be approximately 10-20 % higher than the f value. If you raise
the Ck setting in the Calibration Menu, then the fi value will
increase. The fi is a low pass filter, so by increasing it or
lowering it, you can alter the range of frequencies that the
meter will accept. If the vortex signal is strong, the fi value
will increase to a large number – this is correct.
% change to final value
in one second
= 100 (1 – e
(-1/TC)
)