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WIKA Operating Instructions - Ultrasonic Flowmeter FLC-UFL
81500908.01 08/2020 EN
EN
7. Operation of the local user interface / 8. Maintenance
7.4.5 USB Service mode
When USB Serv. Mode is highlighted and selected using
the
<down> and then <ENT>, the FLC-UFL series
flowmeter will enter the USB service mode, enabling
communications via the USB port.
A message “USB Service Mode” will be shown on the
display.
When pressing
<ENT> again the FLC-UFL series
flowmeter will revert to the normal operation mode.
The dedicated software can be used to communicate via
the USB port when in USB service mode.
7.4.6 Clearing errors
In the event an alarm or warning condition is active,
the diagnostic code (refer to appendix A) is shown on the
lower part of the LCD display until it is acknowledged by
the user. Acknowledging alarms or warnings can be done via
the main menu option 4 – Clear Alarms. If the error condition
is still active the alarm or warning cannot be cleared.
8. Maintenance
The FLC-UFL series ultrasonic flowmeter contains no moving
parts. The sensors and electronics are virtually maintenance
free, however periodic inspection is recommended at regular
intervals.
By collecting a short log file of measurement and diagnostic
data at known and repeatable conditions the meter’s health
status can be observed.
8.1 Inspection of measurement and diagnostic data
By comparing diagnostic data with previously collected
data a good indication of the flowmeter’s condition can
be observed. Below chapters outline the most significant
diagnostic indicators.
The display of diagnostic data is described in section 6.4.3
or may downloaded from the USB port or RS485 optional I/O
port using a Modbus protocol.
For the Modbus map or the dedicated software PC tool
to download diagnostic and flow information contact
Euromisure.
8.1.1 Performance
This diagnostic indicates the percentage of accepted
ultrasonic signals per path. The lower limit is set to 20% by
default. At high flows or very turbulent flows, some rejection
of ultrasonic signals may occur. The performance indicator
is available for each path.
8.1.2 Velocity of Sound (VoS)
The FLC-UFL series flowmeter calculates the average
velocity of sound (VoS) based on the individual measuring
paths. The average VoS is simply the average of the paths.
Individual VoS for each path is also provided. Under normal
conditions the individual path velocities should be reading
very close. When possible the theoretical velocity of sound
using AGA-10 calculations based on temperature, pressure
and gas composition may be compared to the measured
average VoS.
8.1.3 Gas Velocity (VoG)
When possible the meter can be isolated from flowing
conditions (using block valves). In this condition the meter
should read less than 0.01 m/s. This is however extremely
difficult to check due to natural convection inside the pipe
and Flowbody as a result of slight temperature differences,
causing the gas to circulate in the blocked pipe section.
8.1.4 Gain (AGC AB and AGC BA)
For each transducer the required gain in the receiver is
