Instructions
© PCE Instruments 
28 
English 
5  Operation 
5.1  Principle of measurement 
The ultrasonic flow meter has been developed to measure the flow velocity of liquids in pipes. The 
non-contact transducers / sensors are placed on the pipes and are thus not subject to any wear and 
tear. 
The  PCE-TDS  100H/HS  works  with  two  signal  transducers  (sensors)  which  serve  as  ultrasonic 
transmitters and also as ultrasonic receivers. The sensors are installed on the outer wall of the pipe 
at a defined distance, one below the other. 
The sensors can be installed in Z shape (Z method). In this case, the ultrasound will pass through 
the pipe once. If the sensors are installed in W shape (W method), the ultrasound will pass through 
the pipe four times. When using the Z method, the sensors are placed opposite to each other. The 
sound passes through the pipe or liquid diagonally. The selection of the right method depends on the 
characteristics of the liquid. 
1  Downstream transducer 
2  Flow direction 
3  Upstream transducer 
4  Spacing 
You  can  find  more  detailed  information  on  how  to  place  the  sensors  and  how  to  select  the  right 
method of measurement in chapter 5.3.Sensors. 










