21
Chapter VI Operation
Note
：
The flowmeter would be calibrated and debugged before leaving factory, and its
parameters would be set accurately.
Please carefully read the instructions if necessary.
Non-professionals are not allowed to operate the flowmeter.
6.1
Common Functions
6.1.1 How to Judge its Operating Status
If it displays "*R", it indicates the flowmeter works normally.
If it displays "D", it indicates the flowmeter is carrying out auto gain adjustment before
measurement, it is normal most of the time. If it lasts for a long time, it indicates that the
flowmeter fails.
If it displays "E", it indicates that the flowmeter can’t receive sound wave signals. Please check
the connections and installation of transducers. As for more information, please refer to
“ERRORS”.
6.1.2 Low Flow Cut off
M21 menu is the low flow cut menu. The system considers the flow whose absolute value is
less than this value as "0", so you can set this parameter to avoid false accumulation of
measurement errors of the flowmeter when t
he actual flow is “0”. In general, this parameter
is 0.03m/s. When the flow is more than the low flow cut value, the low flow cut value has
nothing to do with the measurement result and will have no influences on it.
6.1.3 Zero Point Setting
Any flowmeter has a relative zero point. That is to say, when you judge the flow is zero but
the flowmeter doesn’t display zero, this value is called zero point. Of course, as for any flow
meters, zero point is objective, but its value is controllable. If zero point is not “0”, it
will cause
measurement errors. Moreover, the smaller the measured physical quantity, the greater the
error caused by it. Only when zero point is reduced to a certain degree as compared with the
measured physical quantity, the error caused by it could be ignored. As for ultrasonic
flowmeter, when the flow is smaller, error caused by zero point couldn’t be ignored. You
