Manual

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M77

Set duration of key sound 0 … 16959 ms

M85

Maximum flow velocity of the liquid 0 … 6553.5 m/s

M86

Number of ultrasonic waves 0 … 16959. When 0 is set, the meter selects the

number of ultrasonic waves.

M87

Set the noise threshold. -2 mV are recommended here

M88

Shows the received signal

M89

Shows the received signal

M90

View signal strength, signal quality, time ratio in the upper right corner

M91

View ratio between measured and calculated total transit time; if all pipe

parameters have been entered correctly and the sensors have been installed

correctly, the ratio should be around 100 % ±3 %; if not so, check all

parameters and sensor installation

M92

View estimated fluid sound velocity; if there is an apparent difference to the

actual fluid sound velocity, check all parameters and the sensor installation

M93

View total transit time and delta time (transit time difference)

M94

View Reynolds number and pipe factor the device uses

5.3 Sensors

Selection of sensor position

The first step before installation should be finding a suitable position to place the sensors. This is a

requirement for accurate measurement results. Some basic knowledge about the pipes / the plumbing

system is necessary.

The ideal location would be an infinitely long, straight pipe, whereas there must be no entrapped air

(air bubbles) in the liquid. The pipes can either run vertically or horizontally. To avoid inaccuracies due

to turbulence in the liquid, a straight flow-calming section before and behind the measuring point

should be considered. In general, the section in front of the measuring point should be at least 10 x

the pipe diameter and after the measuring point, it should be 5 x the pipe diameter.

The following chart shows examples of good positions:

Pipe routings and sensor position

Upstream

Downstream

x ø

10D

12D

20D

30D