Ametek Thermox Series 2000 WDG-IV User Manual page 115

The term zero value on the display is the value the system read during
the calibrate/verify operation, and the term zero gas is the setpoint value
entered using the Cal Gas Values option from the Calibrate key menu.
4. Press Enter.
The time when the calibration or verification was completed will then ap-
pear on the display:
End time hr:mm
End date mm/dd/yr
If the date or time has not been set, random characters will appear instead
of the time and date when the calibration or verification was completed. If
this occurs, reset the control unit's time and date.
Calibration | 5-15