Dynasonics DXN Portable Ultrasonic Measurement System - Manual (Page 72)

CALIBRATION (CAL) GROUP
Meter Adv Display System Site Log I/O Cal
Factory Transit Doppler Factory Transit Doppler
Figure 95: Advanced Group
Transit
Site Name 0.00 GPM
1/16/2013
2:18 PM
Cal Meter Adv Display System Site Log I/O
Transit Factory Doppler
User Adjustment 1.000
0.000
0.000
Positive
Flow
Reynolds
Correcting
SOS
Comp
Soundspeed Offset (us)
Delta Time Zero (ns)
Figure 96: Calibrate Transit Time
Press Delta Time Zero (ns) zeros to remove the No Flow transit time offset. This is also referred to as Zeroing the meter.
Because every flowmeter installation is slightly different and sound waves can travel in slightly different ways through these
various installations, it is important to remove the zero offset at zero flow to maintain the meter’s accuracy. A provision is
made using this button to establish Zero flow and eliminate the offset.
Procedure:
1. The pipe must be full of liquid.
2. Flow must be absolutely zero. Securely close any valves and allow time for any settling to occur.
3. Press the Transit Time Zero button (Delta Time Zero) once.
DXN Portable Ultrasonic Measurement System
Page 72 February 2013