Carrying out the calibration 5  Operation
DMS Go+ Edition 4 (05/2014) 5-25
Probe zero offset
You can choose between automatic and manual probe 
zero offset.
The probe zero offset is not possible if the 
option 2-PT is chosen for the function THK 
CAL. In this case, the function ZERO is not 
visible.
You have a choice between the following methods:
AUTO
This method determines the probe zero offset automat-
ically while the probe is coupled to the material to be 
tested. 
This method requires good coupling conditions and mul-
tiple data acquisitions for determining the ultrasonic 
time of flight. Since this method performs zeroing every 
time a measurement is taken, the zero offset is continu
-
ously adjusted to temperature changes and delay lines.
MANUAL
This method uses the reference block at the instrument 
rear with known wall thickness and sound velocity in or
-
der to determine the zero offset for the connected probe. 
The method is applicable to both single-element probes 
and dual-element probes and it even works in critical 
coupling conditions or with rough surfaces.
USER
When using a clean, uncoupled probe, this method de-
termines the probe zero offset automatically before cou-
pling and only performs zeroing on user request. 
This method works even in critical coupling conditions 
and with rough surfaces.